Behavioural and energetic consequences of competition among three overwintering swan(Cygnus spp.)species

Background:Winter numbers of the northwest European population of Bewick's Swans(Cygnus columbianus bewickii)declined recently by c.40%.During the same period,numbers of two sympatric and ecologically-similar congeners,the Mute Swan(Cygnus olor)and Whooper Swan(Cygnus cygnus)showed increases or stability.It has been suggested that these opposing population trends could have a causal relationship,as Mute and Whooper Swans are larger and competitively dominant to Bewick's Swans in foraging situations.If so,effects of competition of Mute and Whooper Swans on Bewick's Swans should be detectable as measurable impacts on behaviour and energetics.Methods:Here,we studied the diurnal behaviour and energetics of 1083 focal adults and first-winter juveniles("cygnets")of the three swan species on their winter grounds in eastern England.We analysed video recordings to derive time-activity budgets and these,together with estimates of energy gain and expenditure,were analysed to determine whether individual Bewick's Swans altered the time spent on key behaviours when sharing feeding habitat with other swan species,and any consequences for their energy expenditure and net energy gain.Results:All three swan species spent a small proportion of their total time(0.011)on aggressive interactions,and these were predominantly intraspecific(≥0.714).Mixed-effects models indicated that sharing feeding habitat with higher densities of Mute and Whooper Swans increased the likelihood of engaging in aggression for cygnet Bewick's Swans,but not for adults.Higher levels of interspecific competition decreased the time spent by Bewick's Swan cygnets on foraging,whilst adults showed the opposite pattern.When among low densities of conspecifics(<c.200 individuals/km^(2)),individual Bewick's Swans spent more time on vigilance in the presence of higher densities of Mute and Whooper Swans,whilst individuals within higher density Bewick's Swan flocks showed the opposite pattern.Crucially,we found no evidence that greater numbers of interspecific competitors affected the net energy gain of either adult or cygnet Bewick's Swans.Conclusions:We found no evidence that Bewick's Swan net energy gain was affected by sharing agricultural feeding habitat with larger congeners during winter.This was despite some impacts on the aggression,foraging and vigilance behaviours of Bewick's Swans,especially among cygnets.It is unlikely therefore that competition between Bewick's Swans and either Mute or Whooper Swans at arable sites in winter has contributed to the observed decline in Bewick's Swan numbers.Further research is needed,however,to test for competition in other parts of the flyway,including migratory stopover sites and breeding areas.

Multilayer network analysis:new opportunities and challenges for studying animal social systems

Introduction Many behavioral,ecological,and evolutionary processes are closely intertwined with patterns of social interactions,such as the evolution of cooperation(Croft et al.2006),information and disease transmission(VanderWaal et al.2014;Aplin et al.2015),predator-prey dynamics(Ioannou et al.2012),and dispersal decisions(Blumstein et al.2009).Even in species where individuals are traditionally viewed as leading a relatively solitary existence,interac-tions occur across diverse contexts,including territorial defense,resource competition,and courtship.

Genome-wide signatures of the geographic expansion and breeding of soybean

Soybean is a leguminous crop that provides oil and protein. Exploring the genomic signatures of soybean evolution is crucial for breeding varieties with improved adaptability to environmental extremes. We analyzed the genome sequences of 2,214 soybeans and proposed a soybean evolutionary route, i.e., the expansion of annual wild soybean(Glycine soja Sieb. & Zucc.) from southern China and its domestication in central China, followed by the expansion and local breeding selection of its landraces(G. max(L.) Merr.). We observed that the genetic introgression in soybean landraces was mostly derived from sympatric rather than allopatric wild populations during the geographic expansion. Soybean expansion and breeding were accompanied by the positive selection of flowering time genes, including GmSPA3c. Our study sheds light on the evolutionary history of soybean and provides valuable genetic resources for its future breeding.

Understanding bat ecosystem services on a global scale requires caution and wider collaboration:a critical evaluation of Ramírez-Fráncel et al.(2022)

Global biodiversity is currently in the midst of the sixth mass extinction,and countless species and their key ecosystem services are threatened across different habitats(Vos et al.2015).Constructive actions to address the negative impacts of changing conditions require rigorous biodiversity data integration and synthesis to inform effective policy-making decisions(Heberling et al.2021).Care is needed to ensure objectivity and remove biases in analyses to avoid generating misleading conclusions.Recently,Ramírez-Fráncel et al.(2022)published a review offering an update on the vital ecosystem services of bats on a global scale.We applaud the authors for their attempt to conduct an extremely challenging large-scale analysis in major areas of bat ecosystem services.

Molecular evolution and deorphanization of bitter taste receptors in a vampire bat

Bats represent the largest dietary radiation in a single mammalian order,and have become an emerging model group for studying dietary evolution.Taste receptor genes have proven to be molecular signatures of dietary diversification in bats.For example,all 3 extant species of vampire bats have lost many bitter taste receptor genes(Tas2rs)in association with their dietary shift from insectivory to sanguivory.Indeed,only 8 full-length Tas2rs were identified from the high-quality genome of the common vampire bat(Desmodus rotundus).However,it is presently unknown whether these bitter receptors are functional,since the sense of taste is less important in vampire bats,which have an extremely narrow diet and rely on other senses for acquiring food.Here,we applied a molecular evolutionary analysis of Tas2rs in the common vampire bat compared with non-vampire bats.Furthermore,we provided the first attempt to deorphanize all bitter receptors of the vampire bat using a cell-based assay.We found that all Tas2r genes in the vampire bat have a level of selective pressure similar to that in non-vampire bats,suggesting that this species must have retained some bitter taste functions.We demonstrated that 5 of the 8 bitter receptors in the vampire bat can be activated by some bitter compounds,and observed that the vampire bat generally can not detect naturally occurring bitter compounds examined in this study.Our study demonstrates functional retention of bitter taste in vampire bats as suggested by cell-based functional assays,calling for an in-depth study of extra-oral functions of bitter taste receptors.

Balancing timeliness of reporting with increasing testing probability for epidemic data

Reporting of epidemiological data requires coordinated action by numerous agencies,across a multitude of logistical steps.Using collated and reported information to inform direct interventions can be challenging due to associated delays.Mitigation can,however,occur indirectly through the public generation of concern,which facilitates adherence to protective behaviors.We utilized a coupled-dynamic multiplex network model with a communication-and disease-layer to examine how variation in reporting delay and testing probability are likely to impact adherence to protective behaviors,such as reducing physical contact.Individual concern mediated adherence and was informed by new-or active-case reporting,at the population-or community-level.Individuals received information from the communication layer:direct connections that were sick or adherent to protective behaviors increased their concern,but absence of illness eroded concern.Models revealed that the relative benefit of timely reporting and a high probability of testing was contingent on how much information was already obtained.With low rates of testing,increasing testing probability was of greater mitigating value.With high rates of testing,maximizing timeliness was of greater value.Population-level reporting provided advanced warning of disease risk from nearby communities;but we explore the relative costs and benefits of delays due to scale against the assumption that people may prioritize community-level information.Our findings emphasize the interaction of testing accuracy and reporting timeliness for the indirect mitigation of disease in a complex social system.

Genomic analysis of Tibetan ground tits identifies molecular adaptations associated with cooperative breeding

Cooperative breeding is a sophisticated altruistic social behavior that helps social animals to adapt to harsh environments.The Tibetan ground tit,Pseudopodoces humilis,is a high-altitude bird endemic to the Tibetan plateau.Recently,it has become an exciting system for studying the evolution of facultative cooperative breeding.To test for molecular adaptations associated with cooperative breeding,we resequenced the whole genome of ground tits from 6 wild populations that display remarkable variation in the frequency of cooperative breeding.Population structure analyses showed that the 6 populations were divided into 4 lineages,which is congruent with the major geographical distribution of the sampling sites.Using genome-wide selective sweep analysis,we identified putative positively selected genes(PSGs)in groups of tits that displayed high and low cooperative breeding rates.The total number of PSGs varied from 146 to 722 in high cooperative breeding rate populations,and from 272 to 752 in low cooperative breeding rate populations.Functional enrichment analysis of these PSGs identified several significantly enriched ontologies related to oxytocin signaling,estrogen signaling,and insulin secretion.PSGs involved in these functional ontologies suggest that molecular adaptations in hormonal regulation may have played important roles in shaping the evolution of cooperative breeding in the ground tit.Taken together,our study provides candidate genes and functional ontologies involved in molecular adaptations associated with cooperative breeding in Tibetan ground tits,and calls for a better understanding of the genetic roles in the evolution of cooperative breeding.

Brown planthopper Nilaparvata lugens was concentrated at the rear of the typhoon Soudelor in Eastern China in August 2015

Sometimes, extreme weather is vital for the population survival of migratory insects by causing sudden population collapse or outbreak. Several studies have shown that rice planthopper migration was significantly influenced by typhoons in eastern Asia. Most typhoons occur in the summer, especially in August. In August, brown planthopper Nilaparvata lugens （Stal） migrates northward or southward depending on wind direc- tion, and thus typhoons can potentially influence its migration process and population distribution. However, this has not yet been studied. This paper reported a case study on the effects of Typhoon Soudelor on the summer migration of N. lugens in eastern China in 2015. The migration pathways of N. lugens were reconstructed for the period under the influence of a typhoon by calculating the trajectories and migration events in eight counties of the Yangtze River Valley region with ancillary information. Trajectory mod- elling showed that most migrants took short distance migrations （less than 200 km） under the influence of the Typhoon Soudelor. Numerous N. lugens migrants were concentrated and deposited at the rear of the typhoon during the last 5 days of Typhoon Soudelor on August 9-13 due to horizontal convergence, and this led to an outbreak population. These results indicated that the N. lugens population was redistributed by the typhoon in the sum- mer and that the population dynamics at the rear of a typhoon should be kept under close surveillance. This study provided insight into migratory organisms adapting to atmospheric features.

Does the scent of a potential mate prevent the resorption of oocytes by apoptosis in Nauphoeta cinerea？

We expect organisms to have evolved mechanisms to gather and use the information available within their environments, to steer resource investment decisions toward the traits that will give the greatest fitness returns. Pheromones are social signals, a common purpose of which is to act as indicators of mate presence. Consequently, pheromones have the potential to act as signals to increase or maintain reproductive investment over that of competing life-history traits. In the cockroach, Nauphoeta cinerea （Oliver）, females pay costs of maintaining investment in reproduction when there are no males, and males produce pheromones that are known to effect female reproductive outcomes. Whether the pheromones have an influence on resource physiology is unknown. We subjected newly eclosed females to either a synthetic blend of male pheromones or control. We dissected females at 7, 12, 17 or 22 days. We measured apoptosis levels and size of all oocytes within the vitellerium, and measured dry fat body mass. Synthetic male pheromone blend did not have an effect on any measure of female reproductive or somatic resource physiology. Although negative results are always problematic, the success of the synthetic pheromone method in the past suggests that females may be insensitive to male pheromones in the pre-oviposition period, and may rely on mating stimulus rather than pheromone as the cue for oocyte maintenance and growth. Previous studies reporting effects of male pheromones on female reproduction suggest that the period of pheromone sensitivity may be between mating and birth.

Male nutritional status does not impact the reproductive potential of female Cnaphalocrocis medinalis moths under conditions of nutrient shortage

In addition to sperm,some accessory substances transferred to females during copulation act as nuptial gifts by passing on valuable nutrients in many insect species.The nutritional status of the males can thus have a great effect on the mating behavior,fecundity and even the longevity of females.However,little is known about the effect of male nutritional status on the female reproductive traits in migratory insect species,particularly when females experience nutrient shortage and have to choose between reproduction and migration.Here,Cnaphalocrocis medinalis,a migratory rice pest in Asia,was studied to explore this issue.Our results showed that in male moths fed with honey solution,their gonads had higher energy content than gonads of starved males,resulting in increased energy content of the bursa copulatrix of females after mating with fed males.Such females showed increased mating frequency,fecundity and longevity compared to females mating with starved males,indicating that male moths deliver nuptial gifts to females and improve their reproductive performance.However,when females were starved,only about 45%mated,with just a single copulation,regardless of male nutritional status.Starved females showed lower fecundity,and a longer pre-oviposition period(indicating a greater propensity to migrate),compared to fed females.However,copulation still significantly extended their longevity.These results suggest that starved females invest in migration to escape deteriorating habitats,rather than investing the nuptial gift to increased fecundity.Our results further our understanding of the reproductive adaptability of migratory insects under conditions of food stress.