Diet Rather than Genetic Status Shapes the Gut Microbiota in Two Congeneric Snakes

Background: Various external and internal factors affect the gut microbiota of animals. The colonization and proliferation of gut microbes have been studied in a diverse array of animal taxa but remain poorly known in snakes. Here, we used the 16S rRNA gene sequencing technology on the Roach 454 platform to analyze the gut microbiota composition using fecal samples collected from three snake groups [gravid females, newly hatched (preprandial) hatchlings and postprandial hatchlings] of two congeneric colubrid snake species (Elaphe carinata and E. taeniura) that are sympatric across a wide range in mainland China. We tested two hypotheses. First, the gut microbiota should not differ between the two species at hatching if the maternal or genetic contribution has no role in affecting post-hatching gut microbial colonization. Second, differences in the gut microbiota between newly hatched (preprandial) and postprandial hatchlings should not exist in both species if the dietary contribution has no role in affecting post-hatching gut microbial colonization.Results: The top three dominant phyla were Firmicutes, Bacteroidetes, and Proteobacteria in both species. None of the measured alpha diversity indexes differed among the three snake groups or between the two species. The relative abundance of the gut microbiota differed among the three snake groups and between the two species, and so did the relative abundances of the functions associated with the metabolism, cellular processes and environmental information processing. Evidence from gravid females and hatchlings showed that the gut microbiota composition was similar between the two species. The metabolism held the overwhelming predominance of functional categories at the top level in both species.Conclusion: Only the relative abundance of the gut microbiota differed between the two species, and the gut microbiota composition changed rapidly in postprandial hatchlings and differed among the three snakes groups in both species. From these findings, we may conclude that the dietary rather than the maternal or genetic contribution affects gut microbial colonization in snakes.

Behavioral Responses of a Generalist Pest, Spilosoma Obliqua Walker, Towards the Leaf Surface Wax Chemicals of Three Types of Jute Crop and Implications in Pest Management

Behavioral responses of a generalist pest, Spilosoma obliqua Walker (Lepidoptera: Arctiidae), towards the leaf surface wax chemicals of three types of jute crops (white jute, Corchorus capsularis, tossa jute, C. olitorious,, and mesta jute or kenaf, Hibiscus cannabinus [Malvaceae]) and their implications in pest management was studied under laboratory conditions. The GC-MS and GC-FID analyses of the jute leaf epicuticular waxes indicated the presence of 27 n-alkanes, having chain lengths from n-C14 to n-C36 and 14 free fatty acids (FFAs) having chain lengths from C12:0 to C22:0. Among the identified n-alkanes and FFAs of selected jute cultivars n-C34 (144.397±6.971 µg leaf−1) and C16:1 (37.034±0.848 µg leaf−1) of tossa jute leaves were most abundant. The host preference (white jute> tossa jute > mesta jute) of S. obliqua was evaluated simultaneously by olfactory, visual, and tactile recognition, as valid for other lepidopteran species. For olfaction [females], oviposition [gravid females], and feeding [larvae]) in S. obliqua, the most stimulating combined-synthetic-mixture of epicuticular wax components was represented by 4 n-alkanes (n-C16, n-C18, n-C20, n-C22) and 5 FFAs (C16:1, C16:0, C18:0, C20:0, C22:0) in mixture at leaf equivalent (µg leaf−1) amounts (195.209±2.950 µg, 119.777±1.857 µg, and 50.567±3.508 µg, respectively) in white jute, tossa jute, and mesta jute, respectively. Thus, the present study suggests that the synthetic blends of 4 n-alkanes and 5 FFAs of respective jute crops can be used as lures to develop baited trap as a part of integrated pest management (IPM) of S. obliqua for sustainable jute cultivation.

Culex quinquefasciatus larvae development arrested when fed on Neochloris aquatica

Culex quinquefasciatus is a cosmopolitan species widely distributed in the tropical and subtropical areas of the world. Due to its long history of close association with humans, the transmission of arboviruses and parasites have an important role in veterinary and public health. Adult females feed mainly on birds although they can also feed on humans and other mammals. On the other hand, larvae are able to feed on a great diversity of microorganisms, including microalgae, present in natural or artificial breeding sites with a high organic load. These two particularities, mentioned above, are some of the reasons why this mosquito is so successful in the environment. In this work, we report the identification of a microalga found during field sampling in artificial breeding sites, in a group of discarded tires with accumulated rainwater. Surprisingly, only one of them had a bright green culture without mosquito larvae while the other surrounding tires contained a large number of mosquito larvae. We isolated and identified this microorganism as Neochloris aquatica, and it was evaluated as a potential biological control agent against Cx. quinquefasciatus. The oviposition site preference in the presence of the alga by gravid females, and the effects on larval development were analyzed. Additionally, microalga effect on Cx. quinquefasciatus wild type, naturally infected with the endosymbiotic bacterium Wolbachia (w+) and Wolbachia free (w−) laboratory lines was explored. According to our results, even though it is chosen by gravid females to lay their eggs, the microalga had a negative effect on the development of larvae from both populations. Additionally, when the larvae were fed with a culture of alga supplemented with balanced fish food used as control diet, they were not able to reverse its effect, and were unable to complete development until adulthood. Here, N. aquatica is described as a biological agent, and as a potential source of bioactive compounds for the control of mosquito populations important in veterinary and human health.

Corticosterone secretion in tuatara (Sphenodon punctatus): Influential factors and conservation applications

<p>Animals are regularly exposed to environmental, social and physiological challenges. In reaction to these challenges, individuals adjust their physiology and behaviour to maintain essential processes and optimise fitness. The most widely used indicators of physiological stress in vertebrates are glucocorticoid hormones (corticosterone (CORT) or cortisol), which are commonly referred to as ‘stress hormones’. The use of CORT as a tool to understand how individuals respond to natural or human-caused challenges is central to stress physiology research. Here, I investigated intrinsic and extrinsic factors associated with CORT secretion, CORT secretion as an indicator of physiological response to challenges/stressors, and the value of CORT secretion as conservation tool in an iconic protected reptile (the tuatara, Sphenodon punctatus). A capture-restraint time series revealed a significant CORT response over a 24 h period in male and female (non-gravid and gravid) tuatara. Baseline CORT and the CORT response to capture and restraint (i.e. a standardised capture-stress protocol) were similar between sexes; however, female reproductive condition was correlated with CORT secretion in that higher baseline CORT and a lower CORT response were observed in gravid females. An observational study incorporating data across a wide range of ambient temperatures (from four island sites) confirmed that body temperature (Tb) is positively correlated with baseline CORT in gravid females only, and revealed a positive correlation between the CORT response and higher Tb in all adults. A supporting experimental study showed that acute ambient temperature increase (in which mean Tb reached 21.4±0.4°C) elicits a significant CORT response to capture-restraint in gravid females. These results confirmed that gravid females are not secreting CORT maximally during nesting, but actively modulate secretion. An inter-island comparison of CORT secretion (for four populations) revealed that baseline CORT secretion was similar among populations during the non-breeding and breeding seasons; however, the CORT response to capture-restraint varied significantly among populations. Inter-population variation in testosterone (T) was observed in males (but not females) and was positively linked with increased baseline CORT from the non-breeding season to the breeding season, suggesting male reproductive activity may drive seasonal change of baseline CORT. Significant correlations were observed between the CORT response to capture-restraint (but not baseline CORT) and habitat elements of latitude, tuatara density and seabird abundance and 2) demogenetic factors of sex ratio and genetic diversity. The measurement of CORT as a physiological monitoring tool indicated that short- and long- term dynamics of CORT secretion in tuatara are not altered through translocation to a new island, as the acute CORT response remained stable throughout exposure to cumulative stressors and long-term dynamics of CORT secretion in translocated populations simultaneously mirrored those in source populations. These findings deliver the most detailed study of CORT secretion patterns in tuatara to date. Moreover, as the first study to apply CORT secretion data as an conservation physiology monitoring tool in tuatara, these results serve as a baseline reference for future research and monitoring of conservation efforts.</p>

Corticosterone secretion in tuatara (Sphenodon punctatus): Influential factors and conservation applications

<p>Animals are regularly exposed to environmental, social and physiological challenges. In reaction to these challenges, individuals adjust their physiology and behaviour to maintain essential processes and optimise fitness. The most widely used indicators of physiological stress in vertebrates are glucocorticoid hormones (corticosterone (CORT) or cortisol), which are commonly referred to as ‘stress hormones’. The use of CORT as a tool to understand how individuals respond to natural or human-caused challenges is central to stress physiology research. Here, I investigated intrinsic and extrinsic factors associated with CORT secretion, CORT secretion as an indicator of physiological response to challenges/stressors, and the value of CORT secretion as conservation tool in an iconic protected reptile (the tuatara, Sphenodon punctatus). A capture-restraint time series revealed a significant CORT response over a 24 h period in male and female (non-gravid and gravid) tuatara. Baseline CORT and the CORT response to capture and restraint (i.e. a standardised capture-stress protocol) were similar between sexes; however, female reproductive condition was correlated with CORT secretion in that higher baseline CORT and a lower CORT response were observed in gravid females. An observational study incorporating data across a wide range of ambient temperatures (from four island sites) confirmed that body temperature (Tb) is positively correlated with baseline CORT in gravid females only, and revealed a positive correlation between the CORT response and higher Tb in all adults. A supporting experimental study showed that acute ambient temperature increase (in which mean Tb reached 21.4±0.4°C) elicits a significant CORT response to capture-restraint in gravid females. These results confirmed that gravid females are not secreting CORT maximally during nesting, but actively modulate secretion. An inter-island comparison of CORT secretion (for four populations) revealed that baseline CORT secretion was similar among populations during the non-breeding and breeding seasons; however, the CORT response to capture-restraint varied significantly among populations. Inter-population variation in testosterone (T) was observed in males (but not females) and was positively linked with increased baseline CORT from the non-breeding season to the breeding season, suggesting male reproductive activity may drive seasonal change of baseline CORT. Significant correlations were observed between the CORT response to capture-restraint (but not baseline CORT) and habitat elements of latitude, tuatara density and seabird abundance and 2) demogenetic factors of sex ratio and genetic diversity. The measurement of CORT as a physiological monitoring tool indicated that short- and long- term dynamics of CORT secretion in tuatara are not altered through translocation to a new island, as the acute CORT response remained stable throughout exposure to cumulative stressors and long-term dynamics of CORT secretion in translocated populations simultaneously mirrored those in source populations. These findings deliver the most detailed study of CORT secretion patterns in tuatara to date. Moreover, as the first study to apply CORT secretion data as an conservation physiology monitoring tool in tuatara, these results serve as a baseline reference for future research and monitoring of conservation efforts.</p>

Spontaneous Rupture of the Non Gravid Uterus: A Case Report

Uterine rupture can cause serious morbidity and mortality to the women. A complete uterine rupture is a diagnosis made when all three layers of the uterus are separated, while uterine dehiscence is a similar condition in which there is incomplete division of the uterus that does not penetrate all three layers of the uterus. Uterine dehiscence is most often an occult finding in asymptomatic patients. Mostly the uterine rupture is seen in gravid females however it has been reported in non gravid patients as well. Spontaneous uterine rupture is extremely rare to be seen in non gravid patients, but should be included in the differential diagnosis of acute abdomen and shock in a non pregnant woman of any age due to its catastrophic consequences. In non gravid uterus the most common cause of the uterine rupture is pelvic trauma, uterine myomas, infection or uterine carcinoma. We hereby report a case of 44 years old female with previous 4 caesarean sections who came on12th day of her cycle with heavy bleeding, lower abdominal pain and anaemia. She was found to have small fibroids which were blamed for the menorrhagia and she was admitted for the conservative management. She collapsed on day 2 of admission suddenly and after stabilization of the patient her exploratory laparotomy was done and uterine rupture was detected on the right side of the previous scar. The uterus was repaired as the patient refused for hysterectomy. Her post op recovery was uneventful. Her first periods after the surgery was normal with average amount of blood loss. Key words: Uterine rupture, haemorrhage, non -gravid, caesarean, hysterectomy, laparotomy.

Silencing a Simple Extracellular Leucine-Rich Repeat Gene OsI-BAK1 Enhances the Resistance of Rice to Brown Planthopper Nilaparvata lugens

Many plant proteins with extracellular leucine-rich repeat (eLRR) domains play an important role in plant immunity. However, the role of one class of eLRR plant proteins—the simple eLRR proteins—in plant defenses against herbivores remains largely unknown. Here, we found that a simple eLRR protein OsI-BAK1 in rice localizes to the plasma membrane. Its expression was induced by mechanical wounding, the infestation of gravid females of brown planthopper (BPH) Nilaparvata lugens or white-backed planthopper Sogatella furcifera and treatment with methyl jasmonate or abscisic acid. Silencing OsI-BAK1 (ir-ibak1) in rice enhanced the BPH-induced transcript levels of three defense-related WRKY genes (OsWRKY24, OsWRKY53 and OsWRKY70) but decreased the induced levels of ethylene. Bioassays revealed that the hatching rate was significantly lower in BPH eggs laid on ir-ibak1 plants than wild-type (WT) plants; moreover, gravid BPH females preferred to oviposit on WT plants over ir-ibak1 plants. The exogenous application of ethephon on ir-ibak1 plants eliminated the BPH oviposition preference between WT and ir-ibak1 plants but had no effect on the hatching rate of BPH eggs. These findings suggest that OsI-BAK1 acts as a negative modulator of defense responses in rice to BPH and that BPH might exploit this modulator for its own benefit.

Density-dependent mating behaviors reduce male mating harassment in locusts

Male mating harassment may occur when females and males do not have the same mating objectives. Communal animals need to manage the costs of male mating harassment. Here, we demonstrate how desert locusts in dense populations reduce such conflicts through behaviors. In transient populations (of solitarious morphology but gregarious behavior), we found that nongravid females occupied separate sites far from males and were not mating, whereas males aggregated on open ground (leks), waiting for gravid females to enter the lekking sites. Once a male mounted a gravid female, no other males attacked the pair; mating pairs were thereby protected during the vulnerable time of oviposition. In comparison, solitarious locusts displayed a balanced sex ratio in low-density populations, and females mated irrespective of their ovarian state. Our results indicate that the mating behaviors of desert locusts are density dependent and that sex-biased behavioral group separation may minimize the costs of male mating harassment and competition.

Social modulation of oogenesis and egg-laying in Drosophila melanogaster

Being part of a group facilitates cooperation between group members, but also creates competition for limited resources. This conundrum is problematic for gravid females who benefit from being in a group, but whose future offspring may struggle for access to nutrition in larger groups. Females should thus modulate their reproductive output depending on their social context. Although social-context dependent modulation of reproduction is documented in a broad range of species, its underlying mechanisms and functions are poorly understood. In the fruit fly Drosophila melanogaster, females actively attract conspecifics to lay eggs on the same resources, generating groups in which individuals may cooperate or compete. The tractability of the genetics of this species allows dissecting the mechanisms underlying physiological adaptation to their social context. Here, we show that females produce eggs increasingly faster as group size increases. By laying eggs faster in group than alone, females appear to reduce competition between offspring and increase their likelihood of survival. In addition, females in a group lay their eggs during the light phase of the day, while isolated females lay them during the night. We show that responses to the presence of others are determined by vision through the motion detection pathway and that flies from any sex, mating status or species can trigger these responses. The mechanisms of this modulation of egg-laying by group is connected to a lifting of the inhibition of light on oogenesis and egg-laying by stimulating hormonal pathways involving juvenile hormone. Because modulation of reproduction by social context is a hallmark of animals with higher levels of sociality, our findings represent a protosocial mechanism in a species considered solitary that may have been the target of selection for the evolution of more complex social systems.

Egg Cannibalism Varies With Sex, Reproductive Status, and Egg and Nymph Ages in Arma custos (Hemiptera: Asopinae)

Background: Egg cannibalism is common in nature. In China, Arma custos (Hemiptera: Asopinae) has been widely used as a natural enemy to control agricultural and forestry pests. A previous study showed that adult A. custos devour their eggs. However, no research has investigated the interaction between A. custos cannibalism and egg development. Clarifying the mechanisms involved in egg cannibalism by A. custos improves our understanding of the evolutionary relationships to enable more efficient mass rearing and biological control systems.Results: Virgin females showed a lower egg cannibalism inclination than gravid females. Both virgin and mated females showed a higher egg cannibalism inclination than virgin and mated males. The first and second instar nymphs did not devour eggs. The third, fourth, and fifth instar nymphs devoured eggs. Younger eggs were more readily eaten than older eggs. Neither A. custos nymphs nor female adults consumed all the available eggs, allowing an emergence ratio of &gt;70%.Conclusion:Arma custos females exhibit a higher tendency for egg cannibalism than males. Egg cannibalism varies not only with the developmental stage of the eggs and nymphs but also with sex and reproductive status of A. custos females. These findings help us to better understand the evolutionary relationships in egg cannibalism by A. custos and contribute to the efficient mass rearing and realization of A. custos in biological control systems.