Hot and cold waves decrease sperm production and bias sex ratio in the parasitoid wasp Cotesia typhae (Hymenoptera, Braconidae)

The insulin/IGF-signaling pathway is central in control of nutrient-dependent growth during development, and in adult physiology and longevity. Eight insulin-like peptides (DILP1–8) have been identified in Drosophila, and several of these are known to regulate growth, metabolism, reproduction, stress responses, and lifespan. However, the functional role of DILP1 is far from understood. Previous work has shown that dilp1/DILP1 is transiently expressed mainly during the pupal stage and the first days of adult life. Here, we study the role of dilp1 in the pupa, as well as in the first week of adult life, and make some comparisons to dilp6 that displays a similar pupal expression profile, but is expressed in fat body rather than brain neurosecretory cells. We show that mutation of dilp1 diminishes organismal weight during pupal development, whereas overexpression increases it, similar to dilp6 manipulations. No growth effects of dilp1 or dilp6 manipulations were detected during larval development. We next show that dilp1 and dilp6 increase metabolic rate in the late pupa and promote lipids as the primary source of catabolic energy. Effects of dilp1 manipulations can also be seen in the adult fly. In newly eclosed female flies, survival during starvation is strongly diminished in dilp1 mutants, but not in dilp2 and dilp1/dilp2 mutants, whereas in older flies, only the double mutants display reduced starvation resistance. Starvation resistance is not affected in male dilp1 mutant flies, suggesting a sex dimorphism in dilp1 function. Overexpression of dilp1 also decreases survival during starvation in female flies and increases egg laying and decreases egg to pupal viability. In conclusion, dilp1 and dilp6 overexpression promotes metabolism and growth of adult tissues during the pupal stage, likely by utilization of stored lipids. Some of the effects of the dilp1 manipulations may carry over from the pupa to affect physiology in young adults, but our data also suggest that dilp1 signaling is important in metabolism and stress resistance in the adult stage.

Insect gut microbes play important roles in digestion, metabolism, development, and environmental adaptation. Parasitoid wasps are one of the most important biological control agents in pest control, while the gut microbial species compositions and the associated functions have been poorly investigated. Two endoparasitoid wasps, Cotesia vestalis and Diadromus collaris, parasitize the larval stage and pupal stage of the diamondback moth, Plutella xylostella, respectively. Using whole-genome shotgun metagenomic sequencing, we characterized the gut microbial composition, diversity, and potential functional roles associated with the two parasitoid wasp larvae. The results reveal that Proteobacteria and Firmicutes are the dominant phyla in the gut of C. vestalis and D. collaris larvae, with Rhizobium and Enterococcus being the dominant genera. The putative microbial functions associated with the two parasitoid wasps might play a virtual role in assisting in consuming the host's nutritional composition. The enriched CAZymes family genes are primarily involved in the degradation and synthesis of chitin. Despite the richness of microbial species and communities, the microbes species and the microbial community structure exhibit significant similarity between the two parasitoid wasps and between the parasitoid wasp and the host P. xylostella. Notably, the prevalence of the genus Enterococcus shared among them suggests a possible link of gut microbes between the host and their associated parasitoids. Our study offers insights into the gut microbe-based interactions between the host and parasitoid wasps for the first time, potentially paving the way for the development of an ecologically friendly biocontrol strategy against the pest P. xylostella.IMPORTANCEEndoparasitoid wasps spend the majority of their lifespan within their host and heavily rely on the host's nutrition for survival. There is limited understanding regarding the composition and physiological impacts of gut microbial communities in parasitoid wasps, particularly during the larval stage, which is directly linked to the host. Based on a thorough characterization of the gut microbe and comprehensive comparative analysis, we found the microbial species of the larval parasitoid wasp Cotesia vestalis and the pupal parasitoid wasp Diadromus collaris were similar, sharing 159 genera and 277 species, as were the microbial community structure. Certain of the dominant microbial strains of the two parasitoid wasps were similar to that of their host Plutella xylostella larvae, revealing host insect may affect the microbial community of the parasitoid wasps. The putative microbial functions associated with the parasitoid wasp larvae play an important role in dietary consumption.

Simple SummaryBiocontrol with natural enemies of insect pests needs an optimal reproduction of beneficial insects. Most insects are sensitive to heat, and many males suffer from sperm decrease when exposed to warmth during their development. It is dramatic in hymenoptera because males are issued from the development of unfertilized oocytes and only females develop from fertilized eggs. The sex ratio of populations then results from the availability of sperm for egg laying females. Microplitisrufiventris is a parasite of the cotton worm; this moth is a major pest for cotton fields in Egypt. Because the temperature is high in Egypt, reproduction of M. rufiventris must be studied to optimize its use in the fields. We conducted experiments to measure the sperm number of males after heat periods during their development. It shows that M. rufiventris males have less sperm than controls when they were exposed to 36 °C and 40 °C short periods during their development. Moreover, those males live shorter than males that were maintained at 25 °C. In conclusion, we found, males to be sensitive to heat waves, which results in lower fertility, resulting in a lower availability of sperm for females leading to a sex ratio bias. It may lead to a decrease of the efficacy of biocontrol in cotton fields.Understanding reproduction is essential for controlling pests and supporting beneficial insects. Among the many factors allowing optimal reproduction, sperm availability is key to sex ratio control in hymenopteran parasitoids since males are haploid and only females come from fertilization. Microplitisrufiventris (Hymenoptera; Braconidae) is a solitary endoparasitoid of some noctuids. This insect could be used for the control of the cotton leafworm Spodopteralittoralis. Under controlled conditions, sperm quantity was measured in virgin males at 1, 5, 10, and 15 days; it increases in adult males until the fifth day. Sperm stock of control males increased from 2500 at one day to 6700 at 15 days. With the control climatic condition being 25 °C, we tested the effects of a time-limited increase of temperature that can be found in Egypt (36 and 40 °C) during one day at the early pupal stage. Emerging males had 1500 and 420 sperm at 36 and 40 °C, respectively; both lived shorter than the control. The sperm potential of males is dependent on both age and temperature during the early pupal stage. It could have dramatic consequences on the sex ratio of M. rufiventris in natural and controlled populations.

BACKGROUND:. During muscle contraction, blood flow in the working muscles increases tens of times due to the mechanisms of sympatholysis. However, there are no studies that would quantitatively describe the effect of epinephrine on arterial alpha-adrenergic receptors during sympatholysis against the background of 5-day cold adaptation. AIM: Objective. To study the effect of five-day cold adaptation on the adrenoreactivity of muscle arterial vessels during sympatholysis to different doses of epinephrine. MATERIAL AND METHODS: Material and methods. The experiments were carried out in 4 groups of rabbits. Control group (N1, n = 20) of rabbits. Sympatholysis group (N2, n = 15): electrical stimulation of muscles (frequency 5 Hz, voltage 10 V, L = 5 ms) to induce sympatholysis. Cold adaptation group (N3, n = 15) after 5-day exposure in a climatic chamber (−10 ° C, 6 h / day). Group (N4, n=15): combination of 5 days of cold adaptation with sympatholysis. In all rabbits, the limb muscles were perfused with blood through the femoral artery after ligation of all anastomoses using a constant-flow pump. After the introduction of 8 doses of epinephrine (0.5–30 μg/kg), the adrenoreactivity of the limb arteries was analyzed using the dose-effect reaction in double inverse Lineweaver–Burk coordinates. This allowed us to determine the number of active adrenoreceptors (Pm) and the sensitivity (1/Km) of adrenoreceptors to epinephrine. RESULTS: Sympatholysis after 5 days of cold adaptation (N4) was much less for all doses of epinephrine than without cold (N2), which proved a decrease in blood flow in the working muscles during sympatholysis against the background of cold. Analysis of this mechanism in double inverse Lineuwer-Burk coordinates revealed an increase in the number of active a-ARs (by 1.407 times or 40.7%) to Pm=312.5 mmHg during sympatholysis after cold with Pm=222 mmHg during sympatholysis without cold. At the same time, after cold (N4) during sympatholysis, the sensitivity (1/Km) of alpha-adrenoreceptors to epinephrine increased by 1.632 times (by 63.2%) to 1/Km=0.08 from the value of 1/Km=0.049 during sympatholysis without cold (N2). Complete leveling of sympatholysis after cold with 30 μg/kg epinephrine confirms the critical role of dose-dependent pharmacokinetics of arterial tone regulation under cold stress conditions. CONCLUSION: Conclusion. The obtained data allow us to draw the following conclusion: sympatholysis against the background of 5 days of cold persists, but was less than sympatholysis without cold. Increased adrenergic vasoconstriction after 5 days of cold optimizes heat conservation, but reduces blood flow in the working muscles, which limits physical performance. The discovered mechanisms explain the phenomenon of "early cold asthenia" in individuals with short-term arctic exposure, characterized by a decrease in tolerance to physical activity while maintaining basic hemodynamic homeostasis.

ABSTRACTInsects commonly harbor facultative bacterial endosymbionts, such as Wolbachia and Spiroplasma species, that are vertically transmitted from mothers to their offspring. These endosymbiontic bacteria increase their propagation by manipulating host reproduction or by protecting their hosts against natural enemies. While an increasing number of studies have reported endosymbiont-mediated protection, little is known about the mechanisms underlying this protection. Here, we analyze the mechanisms underlying protection from parasitoid wasps in Drosophila melanogaster mediated by its facultative endosymbiont Spiroplasma poulsonii. Our results indicate that S. poulsonii exerts protection against two distantly related wasp species, Leptopilina boulardi and Asobara tabida. S. poulsonii-mediated protection against parasitoid wasps takes place at the pupal stage and is not associated with an increased cellular immune response. In this work, we provide three important observations that support the notion that S. poulsonii bacteria and wasp larvae compete for host lipids and that this competition underlies symbiont-mediated protection. First, lipid quantification shows that both S. poulsonii and parasitoid wasps deplete D. melanogaster hemolymph lipids. Second, the depletion of hemolymphatic lipids using the Lpp RNA interference (Lpp RNAi) construct reduces wasp success in larvae that are not infected with S. poulsonii and blocks S. poulsonii growth. Third, we show that the growth of S. poulsonii bacteria is not affected by the presence of the wasps, indicating that when S. poulsonii is present, larval wasps will develop in a lipid-depleted environment. We propose that competition for host lipids may be relevant to endosymbiont-mediated protection in other systems and could explain the broad spectrum of protection provided.

Adenosine 3',5'-cyclic monophosphate (cAMP) concentration and 3',5'-cyclic-nucleotide phosphodiesterase (PDE) activity were measured in skeletal muscle, heart, and liver of rats exposed to 1, 3, 5, and 7 days of cold. Cyclic nucleotide concentration increased in fast-twitch red muscle at the same time that PDE activity was decreasing. Nucleotide concentration and enzyme activity of slow-twitch red muscle were not altered by the cold exposure. The PDE activity of fast-twitch white muscle was elevated approximately 50% above control after 1 and 3 days of cold exposure. By the 5th day in the cold, white muscle PDE activity had returned to control levels and remained there through the 7th day of experimentation. cAMP concentration in hearts of cold-exposed rats was significantly (P less than 0.01) elevated above control at all time points measured. Myocardial PDE activity was elevated above control (P less than 0.05) at 1 and 3 days of cold exposure but returned to control levels by the 5th day in the cold. Hepatic cAMP and PDE activity were elevated above control at all time points analyzed. These data suggest that changes in cyclic nucleotide metabolism play a role in attaining homeostasis during acute cold exposure.

Hazelnut, as with many other stored products, are susceptible to infestation by a variety of stored insect pests. Phosphine fumigation is a widely used method to control pests in stored products, including hazelnut kernels. This study aimed to determine the optimal exposure time for phosphine fumigation for management of stored product pests in hazelnuts. Four treatments with different exposure times (3, 4, 5, and 6 days) were conducted using various development stages of Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), Tribolium confusum Jaqcquelin du Val, (Coleoptera: Tenebrionidae), Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), and Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) together with the control group. The trials were conducted in a commercial chamber of a hazelnut processing facility. The insects were placed in plastic containers within jute sacks filled with hazelnuts, fumigations were done under gas-proof sheet and the survival rate was assessed after treatments. The results showed that a 3-day exposure period was sufficient to fully eradicate the pupal and adult stages of O. surinamensis. For T. castaneum, 100% mortality was achieved in both larvae and adults from 3 days of exposure, but the pupal stage required at least 5 days. For T. confusum, all larvae and adults died in all exposure periods, but the pupal stage required at least 4 days. In the case of the moth species, a 100% mortality rate was achieved in the larval and pupal stages of both E. kuehniella and P. interpunctella at all exposure periods. The mortality rate of E. kuehniella eggs was 99% after 3 and 4 days of exposure, and a fumigation period of 5 days was required to control the entire population. However, only 67% of P. interpunctella eggs were controlled after 3 days of exposure. The time and stage factors were found to be significant in the egg stage of P. interpunctella. The results suggest that a 5-day exposure period is the most effective for controlling tested stored product pests in hazelnuts.

Two closely related parasitoid wasp species, Cotesia glomerata (L.) and Cotesia rubecula (Marshall) (Hymenoptera:Braconidae), are different in their associative learning of plant odors. To provide a solid basis for our research on the mechanisms that underlie this difference, we described the morphology of the antennal sensilla of these two species using scanning electron microscopy complemented with transmission electron microscopy. Female and male antennae of both species have the same six types of sensilla. We classified these sensilla as sensilla trichodea without pores, sensilla trichodea with a tip pore, sensilla trichodea with wall pores, sensilla coeloconica type I, sensilla coeloconica type II, and sensilla placodea. We conclude that the morphology, numbers, and distribution of the sensory receptors are highly similar in these two closely related wasp species. Differences between species and sexes occurred only in sensilla placodea numbers. C. rubecula has more sensilla placodea than C. glomerata and males of both species have a larger number and a higher density of sensilla placodea compared to females of the same species.

Poly(A)+ RNA was isolated from 5‐day‐old females of the olive fruitfly Dacus oleae. In vitro translation of mRNA, followed by immunoprecipitation with anti‐vitellin antiserum, demonstrated the synthesis of two vitellogenin polypeptides of 54,000 and 56,000 daltons. In sucrose gradient centrifugation, the vitellogenin mRNA sediments in the 14.4S region that corresponds to an RNA size of approximately 1,600 nucleotides. Translation of poly(A)+ RNA isolated from male flies revealed the presence of small quantities of vitellogenin mRNA, consistent with the finding of vitellogenin in male hemolymph of Dacus. Using the female poly(A)+ RNA population as template, we constructed a cDNA expression library in a lambda gt11 vector, which was screened with anti‐vitellin antiserum. Four recombinant clones were isolated containing inserts of 550–800 bp*, which were identified as vitellogenin cDNA clones by hybrid‐selected translation. All four cDNA clones showed crossreaction with vitellogenin genes of Drosophila melanogaster. The Dacus clones were used as probes to study vitellogenin expression during postembryonic development of Dacus. In females, vitellogenin mRNA appeared at the time of eclosion with increasing accumulation up to the 5th day of adult life; then it reached a plateau. On day 10, the mRNA titer had already started to decrease and on day 25, no vitellogenin mRNA was detectable. In males, vitellogenin mRNA was found up to the 8th day after eclosion, in very low concentrations. No vitellogenin mRNA was present during larval and pupal stages.

Cheiloneurus noxius Compere (Hymenoptera: Encyrtidae) is 1 of 3 described species of Cheiloneurus native to California. It is a solitary, internal hyperparasite of unarmored scale insects through the larvae and pupae of various encyrtid primary parasites. Although C. noxius is an obligatory hyperparasite, a typical oviposition exploration pattern takes place on unparasitized scales. Ovisorption of mature eggs in females held without hosts became evident after 10 days of adult life. Host feeding does not occur, but the adult does feed on the honeydew produced by unparasitized scale insects. The life cycle of C. noxius is about 15 days, there being 3 larval instars. First-stage larvae dissected from young hosts were often enclosed in a membranous sheath which may result from host reactions. Superparasitism of the host was commonly observed. C. noxius regularly laid eggs in 4 species of encyrtid primary hosts provided but not in 2 species of Coccophagus (Aphelinidae). Primary host size profoundly influenced the sex ratio of C. noxius, with smaller hosts tending to favor males. The adult size of C. noxius was often larger than that of the host species it was reared from because of the small weight loss suffered by C. noxius during the pupal stage.

Phospholipase A(2) (PLA(2)) is one of the components of bee venom with a wide range of pharmacological functions. It operates as a major allergen working with other venom components to defend the colony from intruder. In the present study, the cDNA sequence of the Ac-pla(2) gene from cDNA library of the venom gland of Apis cerana was compared with the amplified corresponding region of genomic DNA. The result showed that the Ac-pla(2) gene consisted of four exons and three introns. Southern blot showed that the Ac-pla(2) gene was a single copy per haploid genome. The most active transcription period was during the first 8 days of adults, which correspondingly was the period of sharp increase of PLA(2) protein. ELISA analysis revealed that the PLA(2) was undetectable in pupal stage and the newly eclosed adult, but increased sharply to a maximum of 10-12 mug per honeybee by 8-10 days of adult life, followed by a gradual decrease to 8 mug for the rest of adult life. Transcriptional or post transcriptional regulation is the key step for Ac-pla(2) expression. The early secreted Ac-PLA(2) showed a low degree of post-translational modification; with increasing age, glycosylation was detected by Western blot and glycoprotein staining analysis. Different post-translational modifications were found among different individuals in A. cerana when compared to A. mellifera.

The soft bodies and aquatic habitats of mosquito larvae pose a challenge for applying standard RNA-interference techniques to silence expression of target genes. Here we describe a novel technique for delivering double-stranded RNA into mosquito larvae by exploiting the larva's dehydration tolerance. Larvae were dehydrated in a NaCl solution and then rehydrated in water containing double-stranded RNA. Using larvae of Culex pipiens (L.) we demonstrated the principle by knocking down expression of the gene encoding heat shock protein 90. The knockdown persisted through the pupal stage and into adulthood, with a knockdown of approximately 77% still evident on the third day of adult life. We anticipate that this relatively simple procedure will prove useful for knocking down expression of other genes as well, in larvae of this mosquito and in others.

Growth-blocking peptide: an insect biogenic peptide that prevents the onset of metamorphosis

Infection in Drosophila simulans with the endocellular symbiont Wolbachia pipientis results in egg lethality caused by failure to properly initiate diploid development (cytoplasmic incompatibility, CI). The relationship between Wolbachia infection and reproductive factors influencing male fitness has not been well examined. Here we compare infected and uninfected strains of D. simulans for (1) sperm production, (2) male fertility, and (3) the transfer and processing of two accessory gland proteins, Acp26Aa or Acp36De. Infected males produced significantly fewer sperm cysts than uninfected males over the first 10 days of adult life, and infected males, under varied mating conditions, had lower fertility compared to uninfected males. This fertility effect was due to neither differences between infected and uninfected males in the transfer and subsequent processing of accessory gland proteins by females nor to the presence of Wolbachia in mature sperm. We found that heat shock, which is known to decrease CI expression, increases sperm production to a greater extent in infected compared to uninfected males, suggesting a possible link between sperm production and heat shock. Given these results, the roles Wolbachia and heat shock play in mediating male gamete production may be important parameters for understanding the dynamics of infection in natural populations.

species, Microgramma vacciniifolia (Langsd. et Fisch.) Copel. and Microgramma geminata (Schrad.) R.M.Tryon et A.F.Tryon.M. vacciniifolia is a fern epiphyte with Neotropical geographic range. It occurs in many types of vegetation and also in urban trees. In field work in the restinga (sandy coastal plains) of the Marica Environmental Protection Area, Rio de Janeiro State, Brazil, two morphological types of galls, ellipsoid and ovoid ( Figure 1a, b), were reported. Both galls were collected in a Myrtaceae “thicket” community from June 2008 to August 2009 and transported to the laboratory. Part of the sample was packed in transparent plastic bags with moist cotton and checked daily for adult emergence. The botanical dried specimens were deposited in the herbarium of the Faculdade de Formacao de Professores, UERJ (RFFP) and the zoological material were incorporated into the holdings of the Museu Nacional (MNRJ), Rio de Janeiro, Brazil (Cecidomyiidae), Agencia Paulista de Tecnologia dos Agronegocios (APTA), Ribeirao Preto (wasps) and Instituto Uiracu, Bahia (micromoths).The ellipsoid galls are induced by a micromoth (Microlepidoptera), Tortrimosaica polypodivora (Brown et Baixeras, 2004) (Figure 1a). One parasitoid wasp - Cheloninae (Braconidae) - and one inquiline species - Dasineura sp. (Cecidomyiidae) - are also found in the galls and this is the first record of both being connected to M. vacciniifolia. T. polypodivora also induces galls in another fern, Microgramma squamulosa (Kaulf.) de la Sota (Brown et al., 2004). Maia and Santos (2011) described Primadiplosis microgrammae (Maia, 2011) (Cecidomyiidae, Diptera) ( Figure 1b) as producing the ovoid galls found in M. vacciniifolia. In the present note, we record the occurrence of two parasitoids Torymidae and Tetrastichinae (Eulophidae). Hymenoptera is also recorded in these galls for the first time.Although these new records of wasps are presented at family or subfamily levels, they represent an important contribution due to the scarceness of data on insect-fern interactions in the neotropics. The new data indicate that these interactions are much more complex than our previous knowledge indicated.A compilation of gall midges and host plant species of the neotropical region revealed that 92% of these species were monophagous (inducing galls on a single host plant species) and only 5.6% were oligophagous (Carneiro et al., 2009). There is currently no data available for micromoths.The galls induced by micromoths (ellipsoid) are more frequent than those induced by midges (ovoid). The first galls can be found in M. vacciniifolia occurring in natural areas and urban trees, while the second galls are rare even in natural areas. This fern is cyanogenic. The cyanogenesis always occurs in the leaves and there is variation in the stem ( Santos et al., 2005 ). Studies suggest that insect oviposition is stimulated by cyanoglucosides and these compounds could play an important role in host selection (Honda et al., 1997). In field work in a Clusia “scrub” community, in the Restinga de Jurubatiba National Park (Carapebus municipality, Rio de Janeiro state) another micromoth (not identified) in the pupal stage was found to use the stem of