Unmated Females Research Articles

Mating modifies oxidative stress in the brain and confers protection against Parkinson's Disease in a Drosophila model

Mating exerts profound and multifaceted effects on the physiology of female insects, particularly influencing metabolic alterations and bolstering stress resilience. Drosophila melanogaster has emerged as an excellent model to investigate the mechanism of neurodegenerative diseases. However, interplay between mating and its impact on the Drosophila brain remains a tantalizing enigma, awaiting elucidation. Herein, we reported that mating significantly improved the climbing and jumping activity in mated females compared to the virgins in Drosophila. Mating also reduced oxidative stress in the brain. Based on the results, we found that, mated females exhibited better behavioral performance and fewer loss of dopaminergic (DA) neurons than unmated females in PINK1 RNAi flies, a well-established Parkinson's disease (PD) model. Further study demonstrated that mating led to decreased iron content in the brain, a process associated with decreased Transferrin 1 (Tsf1) and Malvolio (Mvl) and increased ferritin. Additionally, mating inhibited expression of Duox and Nox, two NADPH oxidases in Drosophila. Furthermore, Kr-h1, a transcription factor of JH, acted downstream of mating to regulate genes involved in iron metabolism and NADPH oxidases. Collectively, the findings suggested a pivotal role of mating in regulating iron metabolism and NADPH oxidases in the brain of Drosophila. Consequently, considering mating status is imperative in scientific research, particularly in the context of neurological disorders.

Male condition and seminal fluid affect female host-marking behavior in the Mexican fruit fly

Mating and the transfer of seminal fluid components including male accessory glands (MAGs) proteins can affect oviposition behavior in insects. After oviposition, some species of fruit flies deposit a host-marking pheromone (HMP) on the fruit that discourages oviposition by other females of the same or different species or genus and reduces competition between larvae. However, we know very little about how mating, receiving seminal fluid, or male condition can affect female host marking behavior. Here, we tested how the physiological state of females (mated or unmated), the receipt of seminal fluid, and the condition of the male (wild or sterile) affect oviposition and host-marking behavior (HMB) in Anastrepha ludens (Diptera: Tephritidae). We also determined the efficiency of the host-marking pheromone from mated or unmated females in deterring oviposition. In a further examination of how seminal fluid may be affecting HMB we assessed if there were differences in the size of wild or sterile MAGs and the protein quantity transferred during mating. Our results indicate that receiving seminal fluid increased egg laying and increased time invested in host-marking (HM). Unmated females laid fewer eggs than mated females but invested the same amount of time in depositing host-marking pheromone, which had similar effectiveness in deterring oviposition as that of mated females. Females that mated with sterile males laid the same number of eggs as females that mated with wild males but spent less time depositing host-marking pheromone, which suggests that females detect the condition of the male and invest less in marking hosts. Finally, sterile males had larger accessory glands and transferred more MAGs proteins during mating compared to wild males. Seminal proteins could be manipulating HM behavior and female investment into their current reproductive effort. We are only beginning to understand how male condition and seminal fluid can affect female physiology and maternal investment in HMP.

Mating of unfed, engorged, and partially to fully gravid Aedes aegypti (Diptera: Culicidae) female mosquitoes in producing viable eggs

BackgroundUnderstanding the relationship between blood-feeding and mating is important in effectively managing the most well-adapted vector insect, Aedes aegypti (Linnaeus). Although extensive studies have investigated the behavioural aspects of Aedes such as blood-feeding, mating, and their relationship, several knowledge gaps still exist. Therefore, the present study was undertaken to determine the possibility of successful mating by unfed, engorged, and partially to fully gravid (up to 5 days after blood-feeding with fully developed eggs) female Ae. aegypti mosquitoes and production of viable eggs.MethodsMating of sexually mature adult Aedes aegypti was allowed in three different ways. In control 1, the females were allowed to mate before taking blood meal, and in control 2, the females were not at all allowed to mate. In the experiment, the females were separated into six categories, viz. D-0 to D-5. In D-0, the females were allowed to mate immediately after the bloodmeal and, in D-1, the females were allowed to mate on the first day of blood feeding, likewise, the females of D-2, D-3, D-4 and D-5 were allowed to mate on 2nd, 3rd, 4th and 5th day of blood feeding. Ovitrap was uniformly kept on the 4th day of blood feeding for the cages D-0 to D-3 for 1 h and then removed and for the cages D-4, and D-5, the ovitrap was kept on 4th and 5th day of blood feeding for 1h immediately after mating. The total number of eggs and the total number of hatching were counted. In the subsequent days, the entire experiment was replicated two times with different cohorts of mosquitoes, and the mean value of three experiments was used to draw Excel bars with 5% error bars and also for the statistical analysis.ResultsIt was found that mating just before oviposition was sufficient to produce 1581 eggs (70% compared with control) and fertilize 1369 eggs (85% compared with total eggs laid), which is far higher than the 676 non-hatching (unfertilized) eggs (30%) laid by unmated females. Although mating is not essential for producing eggs, our study shows that even brief exposure to the semen and seminal fluids greatly enhances the oviposition and hatching efficiency, even if the mating occurs just before oviposition. However, those females mating before blood-feeding and those mating after blood-feeding produced 2266 and 2128 eggs, with hatching rates of 96.78% and 95.54%, respectively. Hence, the retention time of seminal fluid in the female seems to influence the number of eggs laid and the number of eggs hatched.ConclusionsIn general, mating is possible in Ae. aegypti even minutes before oviposition and is sufficient to produce a greater number of viable eggs.Graphical

Role of nuclear protein Akirin in the modulation of female reproduction in Nilaparvata lugens (Hemiptera: Delphacidae).

Introduction: Akirin as a highly conserved transcription factor, exerts a profound influence on the growth, development, immune response, and reproductive processes in animals. The brown planthopper (BPH), Nilaparvata lugens, a major pest in rice production in Asia, possesses high reproductive capacity, a critical factor contributing to reduced rice yields. The aims of this study were to demonstrate the regulatory role of Akirin in the reproduction of BPH. Methods: In this study, quantitative PCR (qPCR) was used to detect the mRNA expression of genes. RNA interference (RNAi) was used to downregulate the expression of Akirin gene, and RNA sequencing (RNA-seq) was used to screen for differentially expressed genes caused by Akirin downregulation. Hormone contents were measured with the enzyme linked immunosorbent assay (ELISA), and protein content was evaluated with the bicinchoninic acid (BCA) method. Results: Using BPH genome data, we screened for an Akirin gene (NlAkirin). An analysis of tissue-specific expressions showed that NlAkirin was expressed in all tissues tested in female BPH, but its expression level was highest in the ovary. After inhibiting the mRNA expression of NlAkirin in BPH females, the number of eggs laid, hatching rate, and number of ovarioles decreased. Transcriptome sequencing was performed, following a NlAkirin double-stranded RNA treatment. Compared with the genes of the control, which was injected with GFP double-stranded RNA, there were 438 upregulated genes and 1012 downregulated genes; the expression of vitellogenin (Vg) and vitellogenin receptor (VgR) genes as well as the mRNA expression of genes related to the target of rapamycin (TOR), juvenile hormone (JH), and insulin pathways involved in Vg synthesis was significantly downregulated. As a result of NlAkirin knockdown, the titers of JH III and Ecdysone (Ecd) were downregulated in unmated females but returned to normal levels in mated females. The ovarian protein contents in both unmated and mated females were downregulated. Discussion and conclusion: Our results suggest that NlAkirin affects female BPH reproduction by regulating the mRNA expression of genes related to the Vg, VgR, TOR, JH, and insulin signaling pathways, in addition to the titers of JH III and Ecd. The findings of this research provide novel insights into the regulatory role of Akirin in insect reproductive capacity.

The transfer of male cuticular hydrocarbons provides a reliable cue of the risk and intensity of sperm competition in decorated crickets.

Theoretically, males should increase their ejaculate expenditure when the probability of sperm competition occurring (or risk) is high but decrease ejaculate expenditure as the number of competing ejaculates (or intensity) increases. Here we examine whether male decorated crickets (Gryllodes sigillatus) use cuticular hydrocarbons (CHCs) transferred to females by rival males at mating to assess the risk and intensity of sperm competition and adjust their ejaculate accordingly. Unmated females and those perfumed with CHCs extracted from one, three, or five males could be distinguished chemically, providing a reliable cue of the risk and intensity of sperm competition. In agreement with theory, males mating with these females increased sperm number with the risk of sperm competition and decreased sperm number with the intensity of sperm competition. Similarly, as the risk of sperm competition increased, males produced a larger and more attractive spermatophylax (an important non-sperm component of the ejaculate) but these traits did not vary with the intensity of sperm competition. Our results therefore demonstrate that both sperm and non-sperm components of the male ejaculate respond to the risk and intensity of sperm competition in different ways and that CHCs provide males with an important cue to strategically tailor their ejaculate.

Proactive biological control of spotted lanternfly: Parasitism and host feeding behavior of Anastatus orientalis (Hymenoptera: Eupelmidae) on Lycorma delicatula (Hemiptera: Fulgoridae) egg masses

Lycorma delicatula (Hemiptera: Fulgoridae) is a recognized threat to perennial vine, tree crops, and forest ecosystems. Native to China, L. delicatula has invaded eastern Asian countries (The Republic of Korea [i.e., South Korea] and Japan) and is spreading rapidly through the eastern and mid-western regions of the USA. Stablished populations in these regions present a significant incursion threat to California’s multi-billion-dollar perennial crops (e.g., grape and nut production). As a part of a proactive classical biological control program targeting L. delicatula in California, USA, the egg parasitoid, Anastatus orientalis (Hymenoptera: Eupelmidae), is being evaluated for possible use against this pest should it establish in California. In support of this proactive research, the oviposition and host feeding behavior of A. orientalis was investigated. The effect of time exposure (i.e., 48-, 72-, 96-, 168-hours) on the percentage of eggs parasitized by 7-day old female parasitoids previously exposed to L. delicatula egg masses in presence/absence of a conspecific male was also investigated. Parasitism rates were significantly higher after 96 h of exposure time and offspring sex ratio did not change in any of the treatments (i.e., exposure time, presence/absence of a male). In another experiment, mated and unmated female parasitoids of three different ages (i.e., ≤ 24-, 72- and 120 h of age) were digitally video recorded for 24 h while foraging on L. delicatula egg masses and host use behaviors were quantified. Anastatus orientalis females that were 72 h old (mated) and 120 h (mated and unmated) spent significantly more time antennating and probing/ovipositing in L. delicatula egg masses than younger unmated females. An increase in host feeding behavior was always associated with increased oviposition behavior. No detrimental effects of host feeding on rates of parasitism and A. orientalis offspring emergence were detected. This finding confirms that A. orientalis is a concurrent parasitoid and can use the same host egg for feeding and parasitism. Implications of these results on possible rearing and release strategies of A. orientalis as a biological control agent of L. delicatula are discussed.

Whole transcriptome RNA sequencing provides novel insights into the molecular dynamics of ovarian development in mud crab, Scylla paramamosain after mating

Ovarian development in animals is a complicated biological process, requiring the simultaneous coordination among various genes and pathways. To understand the dynamic changes and molecular regulatory mechanisms of ovarian development in mud crab (Scylla paramamosain), both histological observation and whole transcriptome sequencing of ovarian tissues at different mating stages were implemented in this study. The histological results revealed that ovarian development was delayed in unmated females (60 days after courtship behavior but not mating), who exhibited an oocyte diameter of 56.38 ± 15.17 μm. Conversely, mated females exhibited accelerated the ovarian maturation process, with females reaching ovarian stage III (proliferative stage) 23 days after mating and attained an average oocyte diameter of 132.19 ± 15.07 μm. Thus, mating process is essential in promoting the rapid ovarian development in mud crab. Based on the whole transcriptome sequencing analysis, a total of 518 mRNAs, 1502 lncRNAs, 18 circRNAs and 151 miRNAs were identified to be differentially expressed between ovarian tissues at different mating stages. Notably, six differentially expressed genes (DEGs) associated with ovarian development were identified, including ovary development-related protein, red pigment concentrating hormone receptor, G2/mitotic-specific cyclin-B3-like, lutropin-chorio gonadotropic hormone receptor, renin receptor, and SoxB2. More importantly, both DEGs and targets of differentially expressed non-coding RNAs (DEncRNAs) were enriched in renin-angiotensin system, TGF-β signaling, cell adhesion molecules, MAPK signaling pathway, and ECM-receptor interaction, suggesting that these pathways may play significant roles in the ovarian development of mud crabs. Moreover, competition endogenous RNA (ceRNA) networks were constructed while mRNAs were differentially expressed between mating stages were involved in Gene Ontology (GO) biological processes such as developmental process, reproduction, and growth. These findings could provide solid foundations for the future development of female mud crab maturation enhancement strategy, and improve the understanding of the ovarian maturation process in crustaceans.

Spatio-temporal distribution of adults and eggs of the West Indian sweetpotato weevil Euscepes postfasciatus (Coleoptera: Curculionidae) on sweet potato stems

The West Indian sweetpotato weevil, Euscepes postfasciatus, a serious pest of sweet potatoes, is being eradicated by sterile insect technique (SIT) in the south-western islands of Japan. Information on the diurnal movement of the target pests on host plants and where mating and egg-laying behavior occurs on the host is important for the application of SIT, which eradicates the target pest through mating of released sterile males and wild females. However, little such information is available on this species. In this study, male and female adults were released on host plants to examine the diurnal distribution on seedlings according to sex, as well as the sites where mounting behavior and egg laying occurs. The results showed that females left the host plant more frequently at night, whereas males were more likely to remain on the host plant at night. Both males and females stayed on the nodes of the host plant during the daytime. Mounting behavior also tended to occur more often at nodes. Furthermore, compared to unmated females, mated females stayed at the vertical top of the seedlings. However, it was found that eggs were often laid close to the roots rather than at the top of the vertical stems, even when the seedlings were placed upside down. The results of previous studies and this study will be discussed from the perspective of the application of SIT against E. postfasciatus.

(−)‐myrtenol and (−)‐α‐pinene: Aggregation pheromone components of the cypress bark beetle Phloeosinus aubei

AbstractThe cypress bark beetle, Phloeosinus aubei, is of increasing concern in the European market of scale‐leafed conifers. Neither the reproductive behaviour nor the chemical ecology have been studied in detail so far, and no specific attractant traps are available to monitor the flight of adults. We established that stridulation by males is crucial for acceptance by calling females. To unravel the chemical communication, hindgut extracts from unmated females were analysed by GC‐EAD, using male antennae. Gut extracts and Thuja occidentalis leaf extracts were analysed by GC/MS. Two antennally active compounds from gut extracts were identified as (−)‐myrtenol and (−)‐α‐pinene by enantioselective GC/MS. (−)‐Myrtenol was shown to be female‐specific, while (−)‐α‐pinene was found as a 2:1 mixture with the (+)‐enantiomer also among the volatiles of the host tree, T. occidentalis. To prove that the production of the above compounds in the beetles is related to reproduction, we treated females with JHIII. The gut extracts from these sexually mature females showed elevated levels of (−)‐α‐pinene compared to untreated control groups. Synthetic enantiomers of myrtenol and α‐pinene were tested separately by electroantennography, and all were found to be electrophysiologically active. The attractiveness of different mixtures of these compounds was compared using 4‐arm olfactometer tests: 4:1 mixtures of racemic α‐pinene with either (−)‐ or (+)‐myrtenol were significantly attractive to males and females, respectively. In field tests, multifunnel traps baited with a 5:1 mixture of (−)‐α‐pinene and (−)‐myrtenol caught significantly more males and females than unbaited control traps. We concluded that (−)‐α‐pinene and (−)‐myrtenol are components of a female‐produced aggregation pheromone. EAD activity and behaviour assays indicated that α‐pinene from Thuja is used by the beetles as part of a host plant kairomone. The complex communication system of P. aubei is discussed in a chemoecological context.

Reproductive Behavior and Development of the Global Insect Pest, Cotton Seed Bug Oxycarenus hyalinipennis.

Understanding the fundamental life cycle and reproductive behavior of a pest insect is essential for developing efficient control strategies; however, much of this knowledge remains elusive for a multitude of insects, including the cotton seed bug, Oxycarenus hyalinipennis. Here, we report the results of our comprehensive study on the cotton seed bug's life cycle, including mating behavior, adult lifespan, and egg-to-adulthood development. Our findings showed that adult males and females began mating as early as three days after emerging (75%), and the frequency of mating increased to 100% by the fifth day. Mated females commenced oviposition on cotton seeds as early as two days after mating, with a cumulative mean number of 151 fertile eggs oviposited during the first oviposition cycle. Furthermore, around 10% of eggs from both mated and unmated females remained unfertilized. The first instar nymphs began emerging approximately seven days following oviposition. To track their development, we monitored the newly hatched nymphs daily until they reached adulthood. There were five nymphal stages, which cumulatively took roughly 28 to 30 days. Notably, mating positively influenced the survivorship and lifespan of adult O. hyalinipennis. Mated males and females exhibited median lifespans of 28 and 25 days, respectively. In contrast, unmated males and females only lived for a median lifespan of 9.5 days, about one-third that of the mated O. hyalinipennis. Our study provides key insights into the O. hyalinipennis life history for new IPM strategies.

Intra-horn insemination in the alpaca Vicugna pacos: Copulatory wounding and deep sperm deposition.

Alpacas (Vicugna pacos) are reported to be the rare mammal in which the penis enters the uterus in mating. To date, however, only circumstantial evidence supports this assertion. Using female alpacas culled for meat, we determined that the alpaca penis penetrates to the very tips of the uterine horns, abrading the tract and breaking fine blood vessels. All female alpacas sacrificed one hour or 24 hours after mating showed conspicuous bleeding in the epithelium of some region of their reproductive tract, including the hymen, cervix and the tips of each uterine horn, but typically not in the vagina. Unmated females showed no evidence of conspicuous bleeding. Histological examination of mated females revealed widespread abrasion of the cervical and endometrial epithelium, injuries absent in unmated females. Within one hour of mating, sperm were already present in the oviduct. The male alpaca's cartilaginous penis tip with a hardened urethral process is likely responsible for the copulatory abrasion. The entire female reproductive tract interacts with the penis, functioning like a vagina. Alpacas are induced ovulators, and wounding may hasten delivery of the seminal ovulation-inducing factor beta-NGF into the female's blood stream. There is no evidence of sexual conflict in copulation in alpaca, and thus wounding may also be one of a variety of mechanisms devised by mammals to induce a beneficial, short-term inflammatory response that stimulates blastocyst implantation, the uterine remodeling associated with placental development, and thus the success of early pregnancy.

Mating system induced lags in rates of range expansion for different simulated mating systems and dispersal strategies: a modelling study

Mismatches between current and potential species distributions are commonplace due to lags in the response of populations to changing environmental conditions. The prevailing mating system may contribute to such lags where it leads to mating failure at the range edge, but how active dispersers might mitigate these lags using social information to inform dispersal strategies warrants greater exploration. We used an individual-based model to explore how different mating systems for species that actively search for habitat can impose a filter on the ability to colonise empty, fragmented landscapes, and explored how using social information during dispersal can mitigate the lags caused by more constrained mating systems. The mate-finding requirements implemented in two-sex models consistently led to slower range expansion compared to those that were not mate limited (i.e., female only models), even when mating was polygynous. A mate-search settlement strategy reduced the proportion of unmated females at the range edge but had little impact on rate of spread. In contrast, a negative density-dependent settlement strategy resulted in much faster spread, which could be explained by a greater number of long-distance dispersal events. Our findings suggest that even low rates of mating failure at the range edge can lead to considerable lags in range expansion, though dispersal strategies that favour colonising more distant, sparsely occupied habitat patches may effectively mitigate these lags.

Chemosensory Receptor Expression in the Abdomen Tip of the Female Codling Moth, Cydia pomonella L. (Lepidoptera: Tortricidae).

In insects, the chemical senses influence most vital behaviors, including mate seeking and egg laying; these sensory modalities are predominantly governed by odorant receptors (ORs), ionotropic receptors (IRs), and gustatory receptors (GRs). The codling moth, Cydia pomonella, is a global pest of apple, pear, and walnut, and semiochemically based management strategies limit the economic impacts of this species. The previous report of expression of a candidate pheromone-responsive OR in female codling moth ovipositor and pheromone glands raises further questions about the chemosensory capacity of these organs. With an RNA-sequencing approach, we examined chemoreceptors' expression in the female codling moth abdomen tip, sampling tissues from mated and unmated females and pupae. We report 37 ORs, 22 GRs, and 18 IRs expressed in our transcriptome showing overlap with receptors expressed in adult antennae as well as non-antennal candidate receptors. A quantitative PCR approach was also taken to assess the effect of mating on OR expression in adult female moths, revealing a few genes to be upregulated or downregulating after mating. These results provide a better understanding of the chemosensory role of codling moth female abdomen tip organs in female-specific behaviors. Future research will determine the function of specific receptors to augment current semiochemical-based strategies for codling moth management.

The Orco gene involved in recognition of host plant volatiles and sex pheromone in the chive maggot Bradysia odoriphaga

The insect olfactory recognition system plays a crucial role in the feeding and reproductive behaviors of insects. The odorant receptor co-receptor (Orco), as an obligatory chaperone, is critical for odorant recognition by way of forming heteromeric complexes with conventional odorant receptors (ORs). To investigate the biological functions of Orco in perceiving host plant volatiles and sex pheromone, the Orco gene was identified from the chive maggot Bradysia odoriphaga transcriptome data. Multiple sequence alignment reveals that BodoOrco exhibits an extremely high sequence identity with Orcos from other dipteran insects. The expression of BodoOrco is significantly higher in adults than in larvae and pupae, and the BodoOrco gene is primarily expressed in the antennae of both sexes. Furthermore, the Y-tube assay indicated that knockdown of BodoOrco leads to significant reductions in B. odoriphaga adults' response to all tested host plant volatiles. The dsOrco-treated unmated male adults show less attraction to unmated females and responded slowly compared with dsGFP control group. These results indicated that BodoOrco is involved in recognition of sex pheromone and host plant volatiles in B. odoriphaga and has the potential to be used as a target for the design of novel active compounds for developing ecofriendly pest control strategies.

Female melon fruit flies, Zeugodacus cucurbitae, are attracted to a synthetic chemical blend based on male epicuticular components

The melon fly, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae), is considered to be the most destructive pest of melons and other related cucurbit crops worldwide. Despite the potential of behaviour-based control strategies, little is known about the mechanisms involved in female mate choice. Herein, we investigated the production and chemoreception of cuticular hydrocarbons in both sexes of Z. cucurbitae, and the behavioural responses they induce. We studied the epicuticular composition of virgin males and females, using two-dimensional gas chromatography coupled with mass spectrometric detection. Data were interpreted using multivariate factorial analysis. The differentiation of chemical profiles was consistently observed over time. In young individuals, the chemical profiles did not differ between sexes, while sex-specific differences were noted in mature flies. The fly olfactory sensitivity to these compounds was explored using gas chromatography combined with chopped triple electroantennography and electropalpography detectors. This extensive exploration of the pest olfactory sensitivity highlighted three compounds produced by the male. When blended, they induced a robust positive response in unmated naive females in a six-choice olfactometer. The responsiveness of other Tephritidae species (a polyphagous species Bactrocera dorsalis (Hendel) and the cucurbit specialist Dacus demmerezi (Bezzi)) to whole body extracts of Z. cucurbitae was also investigated. Our findings showed that Z. cucurbitae uses species-specific olfactory receptors to detect male produced compounds. In addition, the palps were sensitive to a female-specific component, 1,7-dioxaspiro[5.5]undecane, which the males produce in minute quantities. Overall, this study provides a starting point for a pheromone-based tephritid lure that targets unmated females. The potential implications for pest management are discussed.

DEVELOPMENTAL PARAMETERS OF TRILOCHAVARIANS (LEPIDOPTERA: BOMBYCIDAE); A PEST OF WEEPING FIG, FICUSBENJAMINA IN PAKISTAN

The developmental parameters of Trilochavarianswere studied on weeping fig, Ficusbenjamina at 26°C ± 1.0 temperature and 65±5% relative humidity. The study showed that female laid 160-270 eggs in 2-6 layers on the dorsal side of the leaves. Some unmated female also laid 15-183 eggs in groups which never developed into larvae. 24 hours prior to hatching, the eggs turned black. Egg incubation period was 3.46±1.22 days on F. benjamina. The high fecundity increased the survival rate of T. varians.There were five larval instars which recorded in this study period. Last two instars caused more damage due to resemblance to hosts parts such as bark. There was a short, fleshy horn on the ninth abdominal segment. The developmental time of first, second, third, fourth and fifth larval instars was 2.44±0.82, 3.56±0.53, 3.72±0.26, 4.54±0.79 and 6.20±0.78 days, respectively. Boat shaped and yellow silken pupation was usually observed. The male and female mean longevity was 6.0 ± 1.171 and 11.4 ± 1.70 days. The dorsal side of the female forewings had pale reddish brown lines. The thorax, head, and abdomen of the female had darker reddish brown coloring than those of the male. Adult hind wings had reddish brown outer edges and were grayish in color. The average lifespan for male and female was 6.23±2.09 and 10.01±0.99 days, respectively. Thecurrent paper will lead to proper management practices for this pest

Molecular detection of reproductive symbionts and parthenogenesis experiments in Tuta absoluta from Argentina: facing potential for sustainable and specific pest control strategies

AbstractTomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a key pest of tomato crops. Specific and environmentally friendly control strategies against this pest, such as the sterile insect technique (SIT), are under development and sexual reproduction has emerged as a key focal point to ensure its success. In the present study, we analyzed four representative T. absoluta populations from Argentina, focusing on the molecular detection of endosymbionts potentially associated with reproductive abnormalities and on determining whether parthenogenesis can occur under laboratory conditions. Larvae of T. absoluta were collected in commercial tomato plantations from La Plata and Mar del Plata (both in Buenos Aires province), Bella Vista (Corrientes province), and Yuto (Jujuy province). Tuta absoluta adults were evaluated by standard PCR for the presence of reproductive endosymbionts (Wolbachia sp., Spiroplasma sp., Arsenophonus sp., Cardinium sp., and Rickettsia sp.). For parthenogenesis assays, 20–23 virgin females from each T. absoluta geographic population were life‐long isolated in Petri dishes with a tomato leaf. Fecundity, fertility, and female longevity were estimated and compared with results from mated females from each population. Our results showed the presence of a unique endosymbiont (Wolbachia sp. supergroup B, sequence type 41). Fecundity of the unmated females was significantly lower than fecundity of mated females in all T. absoluta populations. In addition, unmated females only laid infertile eggs. In conclusion, the absence of parthenogenesis in T. absoluta from representative geographic populations supports the implementation of SIT and mating disruption as effective control strategies against this pest in Argentina.

Reproductive biology of overwintering leaffooted bug Leptoglossus zonatus (Hemiptera: Coreidae) in California.

Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae) is a polyphagous insect pest attacking a wide variety of crops. In California's Central Valley, it is now the dominant leaffooted bug on almonds, pistachios, and pomegranates. Leptoglossus zonatus pest status depends largely on overwintering adult survival and reproductive potential, which determines its population size in spring and early summer when nut crops are particularly susceptible to bug damage. Here, we investigated the overwintering reproductive biology of L. zonatus in laboratory and field experiments to gain information about its ovary development, time of mating, and the impact of low temperatures on egg hatch. With dissections of laboratory-reared L. zonatus, we established a baseline for ovarian development and determined that the size of the spermathecal reservoir is larger in mated than in unmated females. Dissections and behavioral experiments of field-collected material provided evidence of mating events before dispersal from overwintering sites. Laboratory trials showed that temperature significantly impacted L. zonatus egg hatch. Leptoglossus zonatus reproductive biology presented provides valuable information on its population dynamics and dispersal from overwintering sites, and will contribute to the development of monitoring and management tools.

Green Leaf Volatile Function in Both the Natural Defense System of Rumex confertus and Associated Insects’ Behavior

Rumex confertus is a rhizomatous, invasive, and difficult to control plant. Nevertheless, for sustainable agriculture, studies to biologically control R. confertus continue. Towards this, considerable attention has been devoted to investigating the emission of a wide array of volatile organic compounds (VOCs) from herbivore-damaged plants, which are known to induce protection measures in neighboring, undamaged plants. The goals of this study are to (1) determine if the profile of green leaf volatiles (GLVs), which are organic compounds naturally produced by undamaged plants, is similar to that provoked by the chemical stimulants Z-jasmone (ZJA) and dihydrojasmone (DJA), (2) establish if the Apion miniatum beetle’s reproductive choices are influenced by their sex and mating status, and (3) assess if chemically stimulated GLV emissions can be used as signals to attract pests to R. confertus for biological control purposes. Synthetic forms of naturally produced Z-jasmone (ZJA) and dihydrojasmone (DJA), which can act as either an attractant or a repellent of various species of insects, were used to treat R. confertus. In olfactory analysis, the behavioral responses of individual insects to mated and unmated insects and to two GLV blends were evaluated. It was found that unmated male insects were fairly equally divided between going for food (Y-tube olfactometer arm with a GLV blend) and opportunities for reproduction (Y-tube olfactometer arm with unmated females). However, an increase in the GLV blend concentration attracted the insects. Meanwhile, unmated females were definitely indifferent to food and, independent of the GLV blend dose, were more interested in reproduction. Mated males, even with weak feed stimuli, increased their reproduction activity, in opposition to mated females. We provide evidence that synthetic GLV blends can be used to attract predators, making their use an effective means to biologically control R. confertus. The idea of applying synthetic GLVs as a biological control is based on the insects’ mutual relationships, which work as follows: (i) mated males fully invade the weed, (ii) reproduction-driven females follow the mated males to R. confertus, and (iii) the unmated males follow the females with the purpose to reproduce. Therefore, all insect groups (mated and unmated males and females) can be induced to invade the weed. Upon feeding, the insects will damage the generative organs of R. confertus. We propose that the use of chemical stimulants to increase GLV emissions can be effectively used for weed (here R. confertus) control by attracting a plant pest (here A. miniatum).

DSmad2 differentially regulates dILP2 and dILP5 in insulin producing and circadian pacemaker cells in unmated adult females.

Much is known about environmental influences on metabolism and systemic insulin levels. Less is known about how those influences are translated into molecular mechanisms regulating insulin production. To better understand the molecular mechanisms we generated marked cells homozygous for a null mutation in the Drosophila TGF-β signal transducer dSmad2 in unmated adult females. We then conducted side-by-side single cell comparisons of the pixel intensity of two Drosophila insulin-like peptides (dILP2 and dILP5) in dSmad2- mutant and wild type insulin producing cells (IPCs). The analysis revealed multiple features of dSmad2 regulation of dILPs. In addition, we discovered that dILP5 is expressed and regulated by dSmad2 in circadian pacemaker cells (CPCs). Outcomes of regulation by dSmad2 differ between dILP2 and dILP5 within IPCs and differ for dILP5 between IPCs and CPCs. Modes of dSmad2 regulation differ between dILP2 and dILP5. dSmad2 antagonism of dILP2 in IPCs is robust but dSmad2 regulation of dILP5 in IPCs and CPCs toggles between antagonism and agonism depending upon dSmad2 dosage. Companion studies of dILP2 and dILP5 in the IPCs of dCORL mutant (fussel in Flybase and SKOR in mammals) and upd2 mutant unmated adult females showed no significant difference from wild type. Taken together, the data suggest that dSmad2 regulates dILP2 and dILP5 via distinct mechanisms in IPCs (antagonist) and CPCs (agonist) and in unmated adult females that dSmad2 acts independently of dCORL and upd2.