Copulation Time Research Articles

Sublethal Effects of α-Cypermethrin on the Behavioral Asymmetries and Mating Success of Alphitobius diaperinus.

Sublethal exposure to insecticides can adversely impact various biological and behavioral characteristics of insects. Although α-cypermethrin has been previously tested for its effects on control of Alphitobius diaperinus, there is no knowledge about the effect of this insecticide on its behavioral asymmetries and mating success. Μales at all exposures (control, LC10, and LC30), that first approached their mate, showed right-biased tendency (approached their mate from their right side) in mate recognition. Females, however, showed variation in this behavior between the three exposures. Right-biased tendency of males in all treatment scenarios led to a higher percentage of successful copulations compared to the three other directions. For males that first approached their mate, the insecticide did not affect their lateralization of the first approach but did affect their copulation success. The duration of copulation time was reduced after the exposure to the insecticide, with the longest duration noted in the control females (63.0 s) and the lowest in the α-cypermethrin LC30 females (46.9 s). Moreover, at the α-cypermethrin LC10 exposure, mate recognition time was reduced, as opposed to α-cypermethrin LC30 exposure where mate recognition time was increased. These results can be further utilized to uncover the behavioral impacts of insecticides, enhancing the effectiveness of pest management in warehouses and poultry production facilities.

Characteristics of Venomous Coleopterans and Their Venom with Therapeutic Power (Insecta: Coleoptera)

The medical importance linked to these beetles is because they have a terpene in their hemolymph insect blood that is soluble in various organic solvents, but practically insoluble in water, cantharidin. Only synthesized male cantharidin is stored until mating and transferred to the female at the time of copulation. When molested, these insects expel the toxin through the membranous joints of the body, causing vesicles similar to burns on human skin. Meloid beetles generate a poisonous chemical compound to, among other things, defend themselves from their predators. An international research team involving the Complutense University of Madrid has shown that cantharidin is toxic to several common parasites. The results explain that some birds, such as the great bustard, ingest this type of beetle, among other beneficial properties, due to the antiparasitic activity of cantharidin. The objective of this manuscript was to describe the characteristics of venomous coleopterans and their venom with therapeutic power (Insecta: Coleoptera). This is a narrative review of the literature, which is indicated to explain and discuss a certain subject from a theoretical or contextual perspective, in a to allow the reader to acquire and/or update knowledge on a specific topic. The search for scientific articles that made up this review was carried out on Google Scholar, Biological Abstract, HAL, Qeios, ResearchGate, Scielo, and SSRN. The following descriptors in Health Sciences (DeCS) were used: biological therapy, larva, wound, debridement, and healing. The following inclusion criteria were considered: Original articles and reviews, published nationally and internationally in full, available electronically, and published in Portuguese, English, and Spanish. The exclusion criteria were dissertations, theses, monographs, and conclusion work, duplicates, and those that required payment to access the content in full.

Selected Aspects of Reproductive Behavior of American Mink (Neovison vison) under Artificial Conditions.

Observation and behavioral analysis of animals can be one of the factors taken into consideration when assessing the welfare of animals kept in artificially created breeding conditions. Disturbed welfare and prolonged exposure to stress can lead to the emergence of abnormal behaviors, including reproductive issues. The aim of this study was to examine the mating behavior of male American mink, with regard to the duration of mating and any potential differences with regard to time of day, mating period, number of mating attempts, and time spent with the female. The study material consisted of 12 one-year-old male American minks with pearl coloring and 60 two-year-old females. Observations were conducted using images captured using externally mounted cameras. The video material capturing the activity of males and females during the mating period was analyzed using the Behawior program. The obtained results indicate the presence of individual differences in copulation duration. It was observed that the copulation time increases with successive days of the breeding season and with number of copulations. It was also observed that a longer time spent with the female to initiate copulation, and behaviors such as rubbing or sniffing the female, were associated with a shorter copulation time. The above-mentioned studies provide specific guidelines regarding the management of matings on the farm, demonstrating the feasibility of conducting matings both in the hours before and after noon.

Behavioral and chromatic dynamics describing mating interactions of the south American octopus Robsonella fontaniana (Cephalopoda: Octopodidae)

Cephalopods are characterized by a substantial behavioral flexibility during reproductive interactions; however, for octopods rather few studies have provided empirical information on the mechanisms operating during male–male and male–female encounters. Using the small south American octopus Robsonella fontaniana (∼270 mm total length, ∼70 mm mantle length), we evaluated the mating behavior based on octopuses from central Chile. Eighteen male–female and five male–male interactions were characterized in laboratory using ethograms divided into precopulatory and copulatory stages. Although subjects’ interactions occurred in both treatments, extended mating periods (81–196 min) were only observed in the male–female trials, and specifically, in those involving larger octopuses (39% of the interactions; > 43 mm mantle length). During the precopulatory stage (4–20 min), different behavioral displays were evidenced in 57% of these male–female interactions, including: contact, exhibition of chromatic displays, swimming, and mounting. Larger pairs had longer copulation times, with a maximum of ∼200 min in octopuses of 50 mm mantle length. The observed mating in adult male–female pairs and the practically null interaction between juveniles suggest that a maturity-conditional reproductive behavior (∼43 mm mantle length; ∼38 gr), could be one of the mechanisms modulating mating interactions of R. fontaniana in the wild, potentially influencing aspects such as mate guarding behavior, possible sperm removal or sperm loading.

An Ethogram of the Reproductive Behaviour of the American Mink (Neovison vison) in Farmed Conditions.

Ethograms can serve as benchmarks against which abnormal animal behaviour can be identified, and then normal behaviour can be restored by appropriately modifying the environment in which an individual resides. The aim of the present study was to create an ethogram of the reproductive behaviour of American mink kept in farmed conditions. The research material consisted of 12 one-year-old male American mink, pearl coloured, selected randomly from among the varieties of coloured mink on the farm, and 60 two-year-old females. The animals participating in the study were grouped into two breeding sets, each consisting of 30 females and 6 males. Reproductive rituals included chasing the female, grasping her neck with the teeth, marking the local area, mounting the partner, and sniffing the neck, anal and genital areas. The copulation times recorded in this study varied greatly, ranging from several minutes to over two hours. The obtained results indicate that the American mink can express some natural reproductive behaviour in breeding conditions, which may also be an indicator of the welfare of these animals.

Copulatory behaviour and seminal parameters of rapid ejaculator rats during competition and female pacing

Axioms of sperm competition theory (risk and intensity model) predict that males increase sperm expenditure when ongoing competitive copulating encounters with other males. Particularly, the intensity model that considers a real male confrontation has not been experimentally tested in laboratory rats. Furthermore, no study has explored the active role of the female (that occurs in natural conditions) in regulating the timing of copulation on the effects of competition on sexual behaviour and seminal parameters. Thus, the goal of this study was to analyse the copulatory behaviour and seminal parameters under male–male competition and female pacing. In order to control for possible variations due to the sexual behaviour phenotype, all experiments were done in male rats with short ejaculation latencies (rapid ejaculators). The results show that competition decreased by half the ejaculation latency and increased sperm quantity, but substantially decreased sperm motility. On the contrary, when competition is tested under conditions where the female regulates the timing of copulation (paced mating), the ejaculation latency increased to double, the sperm count did not change, and the sperm motility significantly decreased. The variations in the parameters of the ejaculate depend on the context, i.e., the confrontation with a competitor, and the active participation of the female during copulation. Probably, when there is more than one male during mating, the female – through cryptic choice – promotes mechanisms that interfere temporally with sperm motility.

Biological evidences for successive oogenesis and egg-laying of Matsumurasca onukii.

Tea plant (Camellia sinensis) is one of the most important horticultural cash crops, and tea green leafhopper (Matsumurasca onukii) is an extremely harmful sap-sucking pest of tea plant. Serious generation overlapping, which is mainly caused by the long oviposition period, leads to poor control effect of pesticides on this pest in the tea plantation. But the intuitive evidences of continuous oogenesis and egg-laying of this pest are still lacking, which seriously hindered the development of genetic control methods. Here, we clarified the main structures of the inner reproductive system of tea green leafhopper female adult. Oviposition behaviors were monitored as well, and six oviposition steps were recorded. According to the maturity of oocytes, the maturity stages of the reproductive system under different copulation periods were classified into 4 stages. For female adults at stage IV, mature and immature oocytes were presented simultaneously, and the developmental levels of oocytes were asynchronous among different ovarioles. The proportion of gravid females with mature oocytes significantly increased when the continuous copulation time was prolonged. In sync with the development of the ovary maturity, female adults started to slightly deposit eggs at the 5th day, and then increased dramatically. In addition, we found that, whether mature or immature, oocytes in the ovarioles always emitted green fluorescence under blue light excitation, which in turn provide solid proof for the new egg detection method from the insect physiology point of view.

Bioassay comparative dose efficacy of Lufenuron on the biology of Spodoptera litura (F.) on cauliflower

The common cutworm Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae), was first described by Johan Christian Fabricius in 1775, is a nocturnal moth, polyphagous in nature, destructive insect pest, damaging economically important crops, and decreasing the yield completely. The research was conducted to control through sub-lethal doses of Lufenuron under laboratory conditions where mortality was determined. The results indicated that the Lufenuron treatment caused mortality, reduction in larval and pupal weight. The copulation time, fecundity, and fertility decreased as compared to control. The maximum mortality was found on dose one after one week and minimum on dose five after 24 hours. The maximum larval weight reductions were recorded in dose one after one week, and dose three after 24 hours with the longest larval and pupal period in dose one and the shortest in dose five as compared to control. The maximum pupal weight reduction was recorded in dose one and minimum in dose five as the shortest adult longevity of S. litura in dose one and the longest in dose five thus; the longest duration of life-cycle in dose one and the shortest in dose five. The shortest copulation time in dose one and the highest in dose five with the minimum fecundity found in dose one and maximum in dose five whereas; minimum fertility of eggs in dose one and maximum in dose five as compared to control. It is concluded that the Lufenuron (IGR) is effective by their sub-lethal concentrations on S. litura however, the most preference can be given to which caused highly sub-lethal effects on its biology. Keywords: Cauliflower; Different doses; Lufenuron; Laboratory conditions; S. litura http://dx.doi.org/10.19045/bspab.2021.100121

Observations of the mating behavior of Portunus trituberculatus and the role of shelters in its mating process

In this study, the mating behavior of Portunus trituberculatus under indoor conditions and the role of shelters in its mating process were systematically studied by using behavioral observation methods. The results showed that the mating behavior of P. trituberculatus was divided into four stages: courtship and pre-copulatory guarding, reproductive moulting, copulation, and post-copulatory guarding. P. trituberculatus in the no shelter group (NSG) usually preferred to gather at the edges or corners of the cement tank, while P. trituberculatus in the shelter group (SG) preferred to hide in the shelters. During the whole experiment, the shelter occupancy rate of P. trituberculatus during the day (57.40%) was significantly higher than that at night (38.08%) (P < 0.05). In terms of hiding rate, the hiding rate was as high as 63.32% during the day, which was significantly higher than that at night (37.70%) (P < 0.05). The copulation time of the SG was similar to that of the NSG. However, the durations of the pre-copulatory guarding period and post-copulatory guarding period of the SG were shorter than those of the NSG, indicating that the presence of shelters could shorten the total mating duration of P. trituberculatus. P. trituberculatus provided with shelter did not hinder its mating behavior, and there was little difference in mating rate between NSG and SG, which were 100% and 97.22%, respectively. In addition, we found that there was certain cannibalism during the reproductive moulting of female crabs, which could lead to the death or injury of some individuals. However, the survival rate of the SG (89.58%) was significantly higher than that of the NSG (72.92%) (P < 0.05). Moreover, the injury rate in the SG was only 14.13%, which was significantly lower than that in the NSG (31.31%) (P < 0.05). In general, shelters have the capability of appealing to P. trituberculatus during mating and can effectively reduce the incidence of intraspecific cannibalism during mating and improve the survival rate of P. trituberculatus.

Efecto de la duración de cópula en la respuesta ovulatoria y tasa de preñez en alpacas

An experiment was carried out at the Experimental Center La Raya-Universidad Nacional del Altiplano Puno, to determine the effect of copulation duration on ovulation and pregnancy in alpacas. 47 adult females were used (postpartum time ≥ 20 days and presence of a follicle ≥ 7 mm) distributed in three groups, according to copulation time: 20, 35 and 50 min, for G1 (n = 15), G2 (n = 16) and G3 (n = 16), respectively. For the mating, 6 reproducers of proven fertility were used, interrupting the copulation at the established time. Ovulation and pregnancy rates were evaluated on days 7 and 30 post service respectively (by ultrasound and receptivity of the female), the data were analyzed using X2 and simple correspondence. Both the ovulation rate (G1: 73.33%, G2: 81.25% and G3: 81.25%); and pregnancy (G1: 53.33%, G2: 81.25% and G3: 75%) were not different (P&gt; 0.05). Pregnancy rates between G1 and G2 tended to be different (P &lt;0.10), consistent with the simple correspondence analysis. Despite there being no differences in ovulation and pregnancy rates, there was a higher percentage trend in G2 and G3, suggesting that the longer duration of mating would have some positive effect on them, according to the simple correspondence analysis, and the trend of low significance (P &lt;0.10) in favor of pregnancy in G2 compared to G1. In conclusion, there were no significant differences in the effect of copulation duration on ovulation; however, there was a 90% trend for the difference between mating duration of 35 minutes versus 20 minutes (in pregnancy).

Ewe Vaginal Microbiota: Associations With Pregnancy Outcome and Changes During Gestation.

Reproductive performance is paramount to the success of livestock production enterprises focused on lamb meat production. Reproductive success is influenced by various factors, possibly including the reproductive tract microbial communities present at the time of copulation and throughout pregnancy. There are few publications that identify the vaginal microbial communities of livestock, and even fewer exist for sheep. To compare ewe vaginal microbial communities, vaginal swabs were taken from 67 Hampshire and Hampshire X Suffolk crossbred ewes from the Iowa State University sheep farm at a pre-breeding time point (S1) and after pregnancy testing (S2). Animals that were determined pregnant were sampled again within a few days of expected parturition (S3). DNA was extracted from these swabs, and 16S rRNA gene Illumina MiSeq amplicon sequencing was conducted to fingerprint the bacterial communities found within this system. Pre-breeding time point samples showed no differences in community structure between animals later found to be pregnant or non-pregnant, but significant changes were detected in species richness (Chao; P < 0.001) and species diversity (Shannon; P < 0.001) at the second sampling time point. A higher microbial diversity within the S2 time point samples may suggest a more stable environment driven by pregnancy, as this increased diversity is maintained in pregnant animals from the S2 to the S3 time point. Additionally, several bacterial phylotypes, such as Mannheimia, Oscillospiraceae-like OTUs and Alistipes, were more abundant at either the S1 or S2 time points in animals that established pregnancy, suggesting a beneficial effect on pregnancy outcome. This study identifies changes within the microbial communities of the ewe vagina before and during gestation and offers inferences on how these changes may impact pregnancy outcome. Information presented herein offers new knowledge about sheep vaginal microbial communities and serves as a starting point to help guide researchers to improve sheep reproductive performance in the future.

Effects of male and female age on mating success in Tetranychus urticae Koch (Acari: Tetranychidae)

Females of most arthropods undergo multiple matings, most often with different males (polyandry) but sometimes with the same male (repeated matings). Arthropod seminal fluid contains components that are known to stimulate their fecundity and fertility. In spider mites, much is known about the paternal effects on offspring phenotypes, but nothing is known about how the age of males affects their fertility. In Tetranychus urticae Koch (Acari: Tetranychidae), the female offspring ratio is known to decrease with time. Here, we attempted to clarify whether the decrease is due to sperm deletion or a decrease in male fertility ability with age. Female age had significantly increase the fecundity. Older virgin females that mated with virgin males produced fewer female offspring. Female age at mating was negatively related to the mating time (= copulation time, sec) but not to the premating time (sec) after introduction of a virgin male. The mating time tended to decrease with increasing age at mating. Male fertility defined as the proportion of female offspring produced, and male fertility declines with male age and number of matings, even no female offspring produced in some cases. These results suggest that increased male age at mating is associated with sperm depletion, which in turn affects the number of progeny as well as the phenotype of the progeny in the subsequent generation.

Asymmetric Phenotypes of Sterile Hybrid Males From Reciprocal Crosses Between Species of the Anopheles gambiae Complex

Haldane’s rule of speciation states that sterility or inviability affects the heterogametic sex of inter-species hybrids. Darwin’s corollary to Haldane’s rule implies that there are asymmetric phenotypes in inter-species hybrids from reciprocal crosses. Studying the phenotypes of F1 hybrids among closely related species of malaria mosquitoes can assist researchers in identifying the genetic factors and molecular mechanisms of speciation. To characterize phenotypes of sterile hybrid males in the Anopheles gambiae complex, we performed crosses between laboratory strains of An. merus and either An. gambiae or An. coluzzii. The reproductive tracts had normal external morphology in hybrid males from crosses between female An. merus and male An. gambiae or An. coluzzii. Despite being sterile, these males could copulate with females for a normal period of time and could transfer a mating plug to induce female oviposition and monogamy. In contrast, the entire reproductive tracts in hybrid males from crosses between female An. gambiae or An. coluzzii and male An. merus were severely underdeveloped. These males had atrophic testes and reduced somatic organs of the reproductive system including male accessary glands and ejaculatory duct. In addition, hybrid males with underdeveloped reproductive tracts displayed a shorter copulation time with females and failed to induce female oviposition and monogamy due to their inability to form and transfer a plug to females during mating. The asymmetry of the phenotypes associated with hybrid male sterility suggests that different genetic factors and molecular mechanisms are responsible for reproductive isolation in reciprocal crosses among species of the An. gambiae complex.

Does Larval Rearing Diet Lead to Premating Isolation in Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae)?

Simple SummarySpodoptera litura Fabricius (Lepidoptera: Noctuidae) is a serious polyphagous pest. Most studies focus on the effects of natural hosts on S. litura. However, progressively more laboratory studies S. litura involve feeding the larvae with an artificial diet. We compared the life performance and observed mating choice of S. litura reared on tobacco, Chinese cabbage, and an artificial diet. The results revealed that diet had a significant effect on the duration of each stage of development. In the multiple-choice test with individual males consuming tobacco, Chinese cabbage, or an artificial diet, females fed on the artificial diet preferred to mate with males that were fed on the same diet and rarely mated with males fed on tobacco or Chinese cabbage. We suggest that the diet of S. litura has a potential impact on mate choice and sexual isolation.Host plant preference during the larval stage may help shape not only phenotypic plasticity but also behavioral isolation. We assessed the effects of diet on population parameters and mate choice in Spodoptera litura. We raised larvae fed on tobacco, Chinese cabbage, or an artificial diet, and we observed the shortest developmental time and highest fecundity in individuals fed the artificial diet. However, survival rates were higher for larvae on either of the natural diets. Population parameters including intrinsic rate of increase and finite rate of increase were significantly higher with the artificial diet, but this diet led to a lower mean generation time. Copulation duration, copulation time, and number of eggs reared significantly differed between diets. In terms of mate choice, females on the artificial diet rarely mated with males fed on a natural host. Our results support the hypothesis that different diets may promote behavioral isolation, affecting mating outcomes. Thus, findings for populations fed an artificial diet may not reflect findings for populations in the field.

106 Exogenous melatonin administration improves behavioural signs, serum melatonin, testosterone, and semen quality in male dromedary (Camelus dromedarius) camels

The present study aimed to evaluate the effects of exogenous administration of melatonin to male camels on reproductive behaviour, seminal parameters, and serum concentrations of melatonin and testosterone during the non-breeding and subsequent breeding seasons. In September 2018, male camels (n=12) were randomly allocated to subcutaneous injections of either melatonin (MLT, 0.643 mg/kg; n=6) dissolved in corn oil, or plain corn oil; (control n=6). The camels were observed for behavioural signs of rut. A second dose of either MLT (1 mg/kg) or corn oil (control) was administered on 7 October 2018 subcutaneously, as camels did not show any change in behaviour until 6 October 2018, and the camels were again observed for behavioural signs of rut. Blood was collected from all camels on 1 September 2018, and then at weekly intervals until 7 January 2019. The serum was separated and stored until further assay of serum melatonin and testosterone using ELISA kits. Semen was collected from camels showing signs of rut period, and the reaction time, copulation time, and seminal parameters were evaluated. Data obtained was analysed by using the computer program SPSS (version 25; IBM Corp.), and means and standard errors were compared. Male reproductive behaviours (protrusion of soft palate, poll gland secretions, frequent urination, increased frothy salivation) were more pronounced in MLT-treated camels (83.33%) than in control camels (50%). Reaction time and copulation times were lower (112.81±30.06s and 229.8±37.91s) in MLT-treated camels than in controls (359.00±41.35s and 301.89±93.90s). Higher semen volume was observed in MLT-treated (5.34±2.06mL) than in control (3.11±1.75mL) camels (P&amp;lt;0.01). Semen collected from MLT-treated camels had more gel formation (81.25%), significantly higher sperm motility (67.50±2.32%), and increased sperm concentration (326.56±38.67 million mL−1) compared with samples obtained from the control males (P&amp;lt;0.01). Serum melatonin concentrations increased in both treated and control camels during the breeding season compared with concentrations before the breeding season. In MLT-treated camels, serum melatonin concentrations increased significantly and continued to be significantly higher than that in control camels for the entire study period (P&amp;lt;0.01). Serum testosterone concentrations were higher in both MLT-treated and control camels during the breeding season compared with those during the non-breeding season (P&amp;lt;0.01). We concluded that exogenous subcutaneous MLT administration improves sexual behaviour, seminal parameters, and serum testosterone concentrations during both the non-breeding and breeding seasons.

Complex interactions between temperature, sexual signals and mate choice in a desert-dwelling jumping spider

Environmental context is a crucial factor that influences sexual communication systems. Particularly in ectotherms, which cannot metabolically regulate their body temperature, temperature has an outsized effect on these intraspecific interactions. Using the desert-dwelling jumping spider Habronattus clypeatus, we assessed how temperature impacts various parts of the male signal and female mate choice for the signal. These spiders have multimodal, temporally structured courtship displays that begin with visual-only ‘sidling’ displays and proceed to multimodal visual and vibratory displays. To examine temperature effects, we performed sequential choice mating experiments (N = 45 trials) at two temperature treatments: hot (∼50 °C) and room temperature (∼25 °C). We found first that variation in the different stages of courtship segregated onto different principal components. The only aspect of male courtship that females expressed preference for was sidling courtship, but only at the higher temperature. Females also preferred to mate with heavier males at all temperatures. Specifically, females preferred to mate with males that performed shorter sidling displays. This is reflected by shorter copulation times in the warm treatment as well. We also found that temperature impacted only vibratory courtship and not sidling courtship. Our results highlight the importance of understanding environmental context in studies of animal communication. We also stress how a holistic, rather than reductive, approach to complex communication systems is vital in order to understand how selection acts upon them.

Differentiation of Multiple Fluorescent Powders, Powder Transfer, and Effect on Mating in Aedes aegypti (Diptera: Culicidae).

Simple SummaryFluorescent powders are one of the most used materials for externally marking mosquitoes, such as Aedes aegypti, a vector of numerous human pathogens. They can be used to explore multiple biological questions related to population size, dispersal, and other interactions related to the spread of mosquito-borne diseases. To ensure marking practical aspects and that these powders do not interfere with mosquito natural behaviors, differentiation of multiple colors applied externally in the same mosquito, their impact on mating, and their transference between individuals after copulation and same-sex interactions were studied. Multiple color differentiation was possible, except for green–yellow combination. No important effect of powder marking was found on any of the mosquito mating phases: coupling (recognition and genital contact), copulation (genitalia engagement and semen transfer), and insemination (deposition of the sperm in the female reservoirs). After copulation with a powder-treated mate, >80% of females and all males had powder in genitalia, legs, and wingtips. The transfer of powder, between same-sex individuals, occurred only in males. In general, fluorescent powders had a little observable effect on Ae. aegypti mating, suggesting that these markers do not alter this important vector life-history trait and are a useful and viable tool for mosquito studies.Five different fluorescent powders (orange, yellow, green, blue, and violet) were tested on Aedes aegypti adults to evaluate the differentiation of multiple fluorescent powder colors applied externally in the same female mosquito, their effect on coupling time, copulation time, insemination success, mate choice, and the extent of transference of powders between marked and unmarked individuals, either during copulation or same-sex interactions. Marking with multiple powders was evaluated after applying different powders in the same female at different times and combinations. The comparative effect of powders on mating was explored using different cross-combinations of marked/unmarked couples. Transference of powders between marked/unmarked individuals after copulation was checked in mated individuals, and between same-sex interactions by allowing them to interact under crowded and uncrowded conditions. Identification of the colors included in multiple markings in the same individual was possible when exploring almost all combinations (exception: green–yellow). No important effect of powder marking between cross-combinations was found on coupling time (overall 95% CI (Confidence Interval) 37.6–49.6 min), copulation time (overall 95% CI 17–20 s), insemination success, nor their mate choice. Transferred powder after copulation activity, concentrated in genitalia, legs, and the tip of wings, occurred in >80% of females and 100% of males. Powder transference in legs and genitalia, between same-sex individuals, occurred only in males (ranged between 23–35%) under both density conditions. The lack of important effects of these powders on the studied aspects of Ae. aegypti provides information about their usefulness and limitations, which should be recognized for future applications and to avoid bias.

The effects of competition on fitness depend on the sex of both competitors

In intraspecific competition, the sex of competing individuals is likely to be important in determining the outcome of competitive interactions and the way exposure to conspecifics during development influences adult fitness traits. Previous studies have explored differences between males and females in their response to intraspecific competition. However, few have tested how the sex of the competitors, or any interactions between focal and competitor sex, influences the nature and intensity of competition. We set up larval seed beetles Callosobruchus maculatus to develop either alone or in the presence of a male or female competitor and measured a suite of traits: development time, emergence weight; male ejaculate mass, copulation duration, and lifespan; and female lifetime fecundity, offspring egg–adult survival, and lifespan. We found effects of competition and competitor sex on the development time and emergence weight of both males and females, and also of an interaction between focal and competitor sex: Females emerged lighter when competing with another female, while males did not. There was little effect of larval competition on male and female adult fitness traits, with the exception of the effect of a female competitor on a focal female's offspring survival rate. Our results highlight the importance of directly measuring the effects of competition on fitness traits, rather than distant proxies for fitness, and suggest that competition with the sex with the greater resource requirements (here females) might play a role in driving trait evolution. We also found that male–male competition during development resulted in shorter copulation times than male–female competition, a result that remained when controlling for the weight of competitors. Although it is difficult to definitively tease apart the effects of social environment and access to resources, this result suggests that something about the sex of competitors other than their size is driving this pattern.

Tomato spotted wilt orthotospovirus influences the reproduction of its insect vector, western flower thrips, Frankliniella occidentalis, to facilitate transmission.

Tomato spotted wilt orthotospovirus (TSWV), one of the most devastating viruses of ornamental plants and vegetable crops worldwide, is transmitted by the western flower thrips, Frankliniella occidentalis (Pergande), in a persistent-propagative manner. How TSWV influences the reproduction of its vector to enhance transmission and whether infection with TSWV changes the mating behavior of F. occidentalis are not fully understood. TSWV-exposed thrips had a significantly longer developmental time than non-exposed individuals. More importantly, increased developmental time was predominantly associated with adults, a stage critical for dispersal and virus transmission. In addition, TSWV-exposed F. occidentalis produced substantially more progeny than did non-exposed thrips. Interestingly, most of the increase in progeny came from an increase in males, a sex with a greater dispersal and virus transmission capability. Specifically, the female/male ratio of progeny shifted from 1.3-7.0/1 to 0.6-1.1/1. As for mating behavior, copulation time was significantly longer in TSWV-exposed thrips. Finally, females tended to re-mate less when exposed to the virus. Resistance to re-mating may lead to reduced sperm availability in females, which translates to a larger number of male progeny under a haplodiploid system. These combined results suggest that TSWV can influence the developmental time, mating behavior, fecundity, and offspring sex allocation of its vector F. occidentalis to facilitate virus transmission. As such, a monitoring program capable of the earlier detection of the virus in host plants and/or its insect vector, thrips, using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), real time quantitative polymerase chain reaction (RT-qPCR) or virus detection strips might be beneficial for long-term, sustainable management. © 2020 Society of Chemical Industry.

Mating behaviour of the leucosiid crabPyrhila pisum(De Haan, 1841)

AbstractMating behaviour of the leucosiid crabPyrhila pisumwas studied in the laboratory and tidal flats in Japan. Most males actively approached females. Males started guarding females without any courtship behaviour (pre-copulatory guarding). Males began copulation within several minutes. The copulation continued for about 1–2 h, following which males began post-copulatory guarding. This guarding lasted from almost 0 to over 3 days, but its duration was generally much longer than that prior to copulation. Release of guarding was not linked to ovulation by females. Long-term rearing experiments revealed that both sexes ofP. pisumcould copulate multiple times with various mates. Developmental stages of the embryos recorded from copulating ovigerous females widely varied; their timing of copulation may not be fixed. In the tidal flat, wandering males frequently contacted with other individuals, but without distinguishing single males, single females and pairs ofP. pisum, orHemigrapsus takanoi. MaleP. pisumcannot recognize female conspecifics, and they approach their mates relying only on vision, without using any attractive cues from females. In cases in which males encountered pairing crabs, they successfully stole the females when the guardians were smaller than the challengers, suggesting that effectiveness of guarding depends on male size. Among the mating pairs, males tended to be larger than females, and the tendency of size-assortative mating was weak or absent. Therefore, the mating behaviour ofP. pisumis not elaborate, although their guarding behaviour may contribute to improve success to some degree.