查看更多>>摘要：Socio-sexual environment can have critical impacts on reproduction and survival of animals.Consequently,they need to prepare themselves by allocating more resources to competitive traits that give them advantages in the particular social setting they have been perceiving.Evidence shows that a male usually raises his investment in sperm after he detects the current or future in-crease of sperm competition because relative sperm numbers can determine his paternity share.This leads to the wide use of testis size as an index of the sperm competition level,yet testis size does not always reflect sperm production.To date,it is not clear whether male animals fine-tune their resource allocation to sperm production and other traits as a response to social cues during their growth and development.Using a polygamous insect Ephestia kuehniella,we tested whether and how larval social environment affected sperm production,testis size,and body weight.We exposed the male larvae to different juvenile socio-sexual cues and measured these traits.We demonstrate that regardless of sex ratio,group-reared males produced more eupyrenes(fertile and nucleate sperm)but smaller testes than singly reared ones,and that body weight and apyrene(infertile and anucleate sperm)numbers remained the same across treatments.We conclude that the presence of larval social,but not sexual cues is responsible for the increase of eupyrene pro-duction and decrease of testis size.We suggest that male larvae increase investment in fertile sperm cells and reduce investment in other testicular tissues in the presence of conspecific juvenile cues.
Toni MINGOZZIPierpaolo STORINoGiampalmo VENUTOAlessandro MASSOLO...
9-17页
查看更多>>摘要：The increase in the average air temperature due to global warming has produced an early onset of the reproduction in many migratory birds of the Paleartic region.According to the"mismatch hypothesis"this response can lead to a decrease in the breeding output when the conditions that trigger the departure from the wintering areas do not match the availability of food resources in the breeding ground.We used 653 brooding events registered during the period 1991-2013 to in-vestigate the link between climatic variables and individual breeding performance of a partially mi-gratory passerine,the Rock Sparrow Petronia petronia,breeding at the altitude limit of its distribu-tion.The laying date(LD)of the earliest first clutch was associated with local spring(minimum)temperatures but did not show a significant trend during the period considered.The LD of the latest first clutch had a positive and statistically significant trend,unrelated to local covariates and result-ing in a longer breeding season(～1.5 days/year).A longer breeding season allowed birds to pro-duce more second clutches,which proportion increased from 0.14 to 0.25.The average breeding success was also positively correlated with the average temperature in July and with the duration of the breeding season.Contrary to expectations,the most important climate-dependent effect was a stretch of the breeding season due to a significant increase of the LD of the latest first-clutches ra-ther than an earlier breeding onset.We show how climate changes act on bird populations through multiple paths and stress the need to assess the link between climatic variables and several aspects of the breeding cycle.
查看更多>>摘要：The benefits of dominance may not come without costs,particularly for males.For example,the"immunocompetence handicap hypothesis"states that males with enhanced mating success allo-cate resources to enhance reproductive output at a cost to their current health,whereas the"resource quality hypothesis"predicts that high-ranking males may benefit from increased repro-duction and good health.Whereas the predictions from each have been well tested in captive ani-mals and in a variety of highly social primates,fewer studies have been carried out in free-living,facultatively social animals.Using adult male yellow-bellied marmots(Marmota flaviventer),we evaluated predictions of these hypotheses by examining the relationship between social rank and 2 health indicators—fecal glucocorticoid metabolite(FCM)levels,and neutrophil/lymphocyte(N/L)ratios—after accounting for variation explained by age,body mass,and seasonality.We found that higher-ranking males tended to have a lower N/L ratio(reflecting good health)than lower-ranking individuals,whereas FCM levels were not significantly related to rank.In addition,heavier male marmots had lower N/L ratios,whereas body mass was not associated with FCM levels.We also found that older adult males had lower FCM levels(reflecting less physiological stress)but higher N/L ratios than younger adults.Finally,we found that FCM levels decreased as the active season progressed and FCM levels were associated with the time of the day.Overall,our results suggest that socially-dominant male marmots enjoyed better,not worse health in terms of lower N/L ratios.
查看更多>>摘要：Characterizing the diversity and structure of host-parasite communities is crucial to understanding their eco-evolutionary dynamics.Malaria and related haemosporidian parasites are responsible for fitness loss and mortality in bird species worldwide.However,despite exhibiting the greatest orni-thological biodiversity,avian haemosporidians from Neotropical regions are quite unexplored.Here,we analyze the genetic diversity of bird haemosporidian parasites(Plasmodium and Haemoproteus)in 1,336 individuals belonging to 206 bird species to explore for differences in di-versity of parasite lineages and bird species across 5 well-differentiated Peruvian ecoregions.We detected 70 different haemosporidian lineages infecting 74 bird species.We showed that 25 out of the 70 haplotypes had not been previously recorded.Moreover,we also identified 81 new host-parasite interactions representing new host records for these haemosporidian parasites.Our out-comes revealed that the effective diversity(as well as the richness,abundance,and Shannon-Weaver index)for both birds and parasite lineages was higher in Amazon basin ecoregions.Furthermore,we also showed that ecoregions with greater diversity of bird species also had high parasite richness,hence suggesting that host community is crucial in explaining parasite richness.Generalist parasites were found in ecoregions with lower bird diversity,implying that the abun-dance and richness of hosts may shape the exploitation strategy followed by haemosporidian para-sites.These outcomes reveal that Neotropical region is a major reservoir of unidentified haemo-sporidian lineages.Further studies analyzing host distribution and specificity of these parasites in the tropics will provide important knowledge about phylogenetic relationships,phylogeography,and patterns of evolution and distribution of haemosporidian parasites.
Javier ABALOSGuillem PéREZ I DE LANUZAAlicia BARTOLOMéFabien AUBRET...
41-55页
查看更多>>摘要：Color polymorphisms are widely studied to identify the mechanisms responsible for the origin and maintenance of phenotypic variability in nature.Two of the mechanisms of balancing selection cur-rently thought to explain the long-term persistence of polymorphisms are the evolution of alterna-tive phenotypic optima through correlational selection on suites of traits including color and heter-osis.Both of these mechanisms can generate differences in offspring viability and fitness arising from different morph combinations.Here,we examined the effect of parental morph combination on fertilization success,embryonic viability,newborn quality,antipredator,and foraging behavior,as well as inter-annual survival by conducting controlled matings in a polymorphic lacertid Podarcis muralis,where color morphs are frequently assumed to reflect alternative phenotypic op-tima(e.g.,alternative reproductive strategies).Juveniles were kept in outdoor tubs for a year in order to study inter-annual growth,survival,and morph inheritance.In agreement with a previous genome-wide association analysis,morph frequencies in the year-old juveniles matched the fre-quencies expected if orange and yellow expressions depended on recessive homozygosity at 2 separate loci.Our findings also agree with previous literature reporting higher reproductive output of heavy females and the higher overall viability of heavy newborn lizards,but we found no evi-dence for the existence of alternative breeding investment strategies in female morphs,or morph-combination effects on offspring viability and behavior.We conclude that inter-morph breeding remains entirely viable and genetic incompatibilities are of little significance for the maintenance of discrete color morphs in P.muralis from the Pyrenees.
查看更多>>摘要：Cutting-edge technologies are extremely useful to develop new workflows in studying ecological data,particularly to understand animal behavior and movement trajectories at the individual level.Although parental care is a well-studied phenomenon,most studies have been focused on direct observational or video recording data,as well as experimental manipulation.Therefore,what happens out of our sight still remains unknown.Using high-frequency GPS/GSM dataloggers and tri-axial accelerometers we monitored 25 Bonelli's eagles Aquila fasciata during the breeding season to understand parental activities from a broader perspective.We used recursive data,measured as number of visits and residence time,to reveal nest attendance patterns of biparental care with role specialization between sexes.Accelerometry data interpreted as the overall dynamic body acceleration,a proxy of energy expenditure,showed strong differences in parental effort throughout the breeding season and between sexes.Thereby,males increased substantially their energetic requirements,due to the increased workload,while females spent most of the time on the nest.Furthermore,during critical phases of the breeding season,a low percentage of suitable hunting spots in eagles'territories led them to increase their ranging behavior in order to find food,with important consequences in energy consumption and mortality risk.Our results highlight the crucial role of males in raptor species exhibiting biparental care.Finally,we exemplify how biologging technologies are an adequate and objective method to study parental care in raptors as well as to get deeper insight into breeding ecology of birds in general.
查看更多>>摘要：Some types of plant accumulate liquid in their inflorescences creating phytotelmata.These envi-ronments protect the flowers against florivory,although they may be colonized by aquatic or semi-aquatic florivorous insect larvae,whose effects on the fitness of the plants remain unclear.We tested the hypothesis of floral antagonism by the occupants of phytotelmata,which predicts that florivory by the occupants of the phytotelmata represents a cost to the female fitness of the plant,reducing its fecundity.We manipulated experimentally the infestation by 3 florivores larvae species occupants of phytotelmata in inflorescences of Heliconia spathocircinata(Heliconiaceae)to test for negative direct trophic effects on the fecundity of the flowering and fruiting bracts.We found that the foraging of the hoverfly(Syrphidae)and moth(Lepidoptera)larvae in the inflorescences con-tributed to a decline in the fecundity of the plant.While the lepidopteran impacted fecundity when foraging in both flowering and fruiting bracts,the syrphid only affected the fruiting bracts,which indicates that the nectar and floral tissue are the principal resource exploited by the hoverfly.By contrast,soldier fly(Stratiomyidae)had a neutral effect on fecundity,while foraging in flowering or fruiting bracts.These findings corroborate our hypothesis,that herbivory by the larval occupants represents cost to the host plant having phytotelmata.The negative influence of this foraging on plant fecundity will nevertheless depend on the consequences of the exploitation of resources,which vary considerably in ephemeral habitats such as the phytotalmanta of flower parts.
Jamille Costa VEIGAGustavo Rodrigo Sanches RUIZGislene Almeida CARVALHO-ZILSECristiano MENEZES...
81-92页
查看更多>>摘要：Males can control female reproduction using genital plugs to impede access by rivals.In social bees,ants,and wasps,plugging may involve traumatic mating,with females being harmed.In stingless bees,chances are that plugs may promote ovarian activan,and are thought to ensure sin-gle mating—a general tendency among the social Hymenoptera.However,understanding on rela-tionships between mating plugs,traumatic mating,and mating systems in stingless bees remains limited.To address this,we(1)compared mated queens of 7 Neotropical species to understand the patterns of copulatory marks in females and(2)compared pre-and post-mating genitalia of males and females in Melipona fasciculata to depict plug functional morphology.Data revealed an unpre-cedented consequence of mating in stingless bees:the characteristic marks left by mating plugs on female abdomens and the inferences that can be made from them.To our surprise,in 1 species M.fasciculata we found that queens retain the plug long after mating,and may carry it for the rest of their lives.All the other 6 species retained the plug for only a short period.Remated queens were only found in M.seminigra,whose multiple copulatory marks match previous findings of polyan-dry in this species.Our study shows that queens can remate,and suggests that male genital morphology may determine in part the time persistence of plugs.We conclude that traumatic mat-ing plugs do not fully prevent remating in stingless bees and that mating systems are not uniform in this group.Nonetheless,exceptional cases of facultative polyandry in social insects—for ex-ample,when mating plugs fail—may confirm a general tendency for single mating in close link with efficient mating plugs.
查看更多>>摘要：When vertebrates face stressful events,the hypothalamic-pituitary-adrenal(HPA)axis is activated,generating a rapid increase in circulating glucocorticoid(GC)stress hormones followed by a return to baseline levels.However,repeated activation of HPA axis may lead to increase in oxidative stress.One target of oxidative stress is telomeres,nucleoprotein complexes at the end of chromo-somes that shorten at each cell division.The susceptibility of telomeres to oxidizing molecules has led to the hypothesis that increased GC levels boost telomere shortening,but studies on this link are scanty.We studied if,in barn swallows Hirundo rustica,changes in adult erythrocyte telomere length between 2 consecutive breeding seasons are related to corticosterone(CORT)(the main avian GC)stress response induced by a standard capture-restraint protocol.Within-individual telo-mere length did not significantly change between consecutive breeding seasons.Second-year indi-viduals showed the highest increase in circulating CORT concentrations following restraint.Moreover,we found a decline in female stress response along the breeding season.In addition,telomere shortening covaried with the stress response:a delayed activation of the negative feed-back loop terminating the stress response was associated with greater telomere attrition.Hence,among-individual variation in stress response may affect telomere dynamics.
查看更多>>摘要：Uncovering mate choice and factors that lead to the choice are very important to understanding sexual selection in evolutionary change.Cicadas are known for their loud sounds produced by males using the timbals.However,males in certain cicada species emit 2 kinds of sounds using re-spectively timbals and stridulatory organs,and females may produce their own sounds to respond to males.What has never been considered is the mate choice in such cicada species.Here,we in-vestigate the sexual selection and potential impact of predation pressure on mate choice in the ci-cada Subpsaltria yangi Chen.It possesses stridulatory sound-producing organs in both sexes in addition to the timbals in males.Results show that males producing calling songs with shorter tim-bal-stridulatory sound intervals and a higher call rate achieved greater mating success.No mor-phological traits were found to be correlated with mating success in both sexes,suggesting neither males nor females display mate preference for the opposite sex based on morphological traits.Males do not discriminate among responding females during mate searching,which may be due to the high energy costs associated with their unusual mate-seeking activity and the male-biased predation pressure.Females generally mate once but a minority of them re-mated after oviposition which,combined with the desirable acoustic traits of males,suggest females may maximize their reproductive success by choosing a high-quality male in the first place.This study contributes to our understanding mechanisms of sexual selection in cicadas and other insects suffering selective pressure from predators.
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