摘要: Male-specific wing spots are usually associated with wing displays in the courtship behavior of Drosophila and may play important roles in sexual selection. Two closely related species, D. nepalensis and D. trilutea, differ in wing spots and scissoring behavior. Here, we compare male morphological characters, pigmentation intensity of male wing spots, wing-scissoring behavior, courtship songs, and reproductive isolation between 2 species. F1 fertile females and sterile males result from the cross between females of D. nepalensis and males of D. trilutea. The pigmentation of wing spots is significantly weaker in D. trilutea than in D. nepalensis and the F1 hybrid. Males scissor both wings in front of the female during courtship, with a posture spreading wings more widely, and at a faster frequency in D. nepalensis than in D. trilutea and the F1s. Males of D. trilutea vibrate wings to produce 2 types (A and B) of pulse songs, whereas D. nepalensis and the F1s sing only type B songs. The incidence of wing vibration and scissoring during courtship suggests that wing vibration is essential but scissoring is a facultative courtship element for successful mating in both species. The association between the darker wing spots with more elaborate scissoring might be the consequence of correlated evolution of these traits in D. nepalensis; however, D. trilutea retains wing scissoring during courtship despite having weaker pigmentation of wing spots. The genetic architecture of 2 traits differs in the F1s, consistent with maternal or sex-linked effects for spots but nonadditive effects for scissoring.

摘要: Many animals consume the feces of their conspecifics. This allo-coprophagy can have benefits, such as access to nutrients and symbionts, but also risks for consumers, mainly due to direct contact with pathogens that develop on feces. In the European earwig Forficula auricularia, mothers and juveniles live in nests lined with their feces. This surprising habit allows juveniles to consume the feces of their siblings during family life and provides them with nutritional benefits when mothers provide low care. However, it was unclear whether earwig mothers also practice allo-coprophagy, and whether this behavior is motivated by their nutritional needs. Here, we set up four types of experimental families in which we manipulated the nutritional needs of mothers and/or juveniles and measured the effects on the production of feces by the juveniles, and the consumption of these feces by the mothers. Our results first show that fed juveniles produced more feces pellet in presence of fed compared to food-deprived mothers. We also found that, overall, about 50% of the mothers consumed juveniles feces. This consumption was both more likely and larger when the feces were produced by fed compared to food-deprived juveniles, while the proportion of feces pellets eaten was larger in food-deprived compared to fed mothers. Overall, our results reveal that allo-coprophagy involves every family member and suggest that it can have both nutritional and non-nutritional benefits for earwig mothers. Allo-coprophagy could thus favor the maintenance of mothers in the nest and, more generally, promote the early evolution of family life.

摘要: Despite the importance of reproduction in insects, its relation with multi-stop flight remains poorly understood in migratory species. To clarify whether reproductive maturation commences during the multi-stop flight or after the completion of migration, we conducted physiological and behavioral assays in the rice leaf roller Cnaphalocrocis medinalis with laboratory-simulated conditions and field-captured populations. We found that the ovarian development was significantly promoted by tethered flight treatment for 1-2 nights when compared to the unflown group, while the flight muscle development was not impaired. There was no significant difference in flight duration, flight distance and flight velocity between mated and virgin female moths, indicating that mated moths remained competent for the subsequent flights as did the virgins. Using an integrated field assay, we identified that over 60% of the female moths in the migrating populations captured by high-altitude searchlights in the Immigration period of a season had completed the ovarian development and mating. Sexually mature and mated moths collected in the rice field in the Emigration period were found capable of engaging in migratory take-off, as observed using an indoor monitoring platform. Overall, our findings point out that C. medinalis managed to complete reproductive maturation to a large extent during the multi-stop migratory flight without compromising the migration performance. Such a cost-effective strategy ensures a successful migration for the moths. These findings advance our understanding of the relationship between reproduction and migration, thus shedding light on the development of novel control measures for the outbreak of migratory insect pests.

摘要: Amblypygi are tropical and subtropical ambush predators that use elongated, raptorial pedipalps for different activities. Although pedipalp use in predation and courtship has been explored in videography in vivo analyses, kinematic ex vivo examination of these appendages has not been conducted. Here, we rectify this lack of data by using micro-CT scans to 3D-kinematically model the appendage morphology and the range of motion (ROM) of the joints for Damon medius and Heterophrynus elaphus. We illustrate the successful application of this technique to terrestrial euarthropods in determining the maximum ROM values for each pedipalp joint. We also note that, in life, these values would be lower due to motion restricting structures like tendons, arthrodial membranes, and muscles. We further compare our maximum values obtained here with data from video-based motion analyses. The ROM of each joint shows the greatest flexibility in the femur-tibia joint (140-150 degrees), the lowest in the basitarsus-claw joint (35-40 degrees). ROM in the tibia-basitarsus joint is markedly distinct (D. medius: 44 degrees; H. elaphus: 105 degrees). This disparity reflects how H. elaphus uses the joint in the capture basket, while D. medius uses the femur-tibia joint to form the capture basket. We further illustrate notable vertical motion of the H. elaphus pedipalp compared to D. medius. This difference reflects the retro-ventral trochanter apophysis of H. elaphus. Our study opens the possibility to further whip spider kinematic understanding. Examination of other taxa using this approach will result in a more comprehensive understanding of the ecological significance and ethological implications of this unique arachnid group.

摘要: Seed traits play an important role in affecting seed preference and hoarding behaviors of small rodents. Despite greatly affected by seed traits, seed detectability of competitors represents pilfering risks and may also modify seed hoarding preference of animals. However, whether seed traits and seed detectability show consistent effects on seed hoarding preference of animals remain largely unknown. Here, we explored how seed traits and seed detectability correlate with seed hoarding preference of Leopoldamys edwardsi and Apodemus chevrieri in a subtropical forest. Despite the effects of seed coat thickness and caloric value on hoarding preference of L. edwardsi, we detected no significant effects of other seed traits on hording preference of the 2 rodent species. There was no correlation between larder-hoarding preference and inter- or intra-specific seed detectability of L. edwardsi; however, seed detectability of L. edwardsi was negatively correlated with its own scatter-hoarding preference. Although scatter-hoarding preference of A. chevrieri was not correlated with inter- and intra-specific seed detectability, larder-hoarding preference of A. chevrieri was positively correlated with intra-specific seed detectability. Our study may provide evidence that intra-specific seed detectability rather than seed traits and inter-specific pilfering risks play an important role in modifying seed hoarding preference of rodents.