摘要: Portschinskia Semenov is a rare genus of bot flies whose larvae are obligate parasites of pikas and murine rodents, crucial for understanding the evolutionary biology of Oestridae. However, limited information on their adult biology and early immature stages has hindered the progress. Here, we provided the first documentation of adult oviposition, behavior, and morphology of newly hatched first instars of P. magnifica Pleske. Using confocal laser scanning microscopy and scanning electron microscopy, we characterized the ultrastructure of egg and first-instar larva, identifying key traits facilitating attachment. Eggs were deposited individually or in groups, and glued on non-host surfaces with white adhesive substances, without specialized attachment organ. Newly hatched first instars were circled with an anterior spinose band on each body segment except the anal division, awaited hosts in an upright position, and anchored to the egg shell by their anal division, likely supported by curved spines originating from the peritreme of the posterior spiracles. Evolutionary analyses of reproductive behavior across the 4 bot fly subfamilies reveal at least 3 times independent evolution of oviposition on non-host surfaces in Portschinskia or the Hypodermatinae clade as a sister group to Ochotonia, Gasterophilus pecorum (Fabricius) (Gasterophilinae), and Cuterebrinae. In contrast, species in the Oestrinae are larviparous, depositing first instars directly onto hosts. Our findings shed light on oviposition behavior and early immature morphology of the rare genus Portschinskia, offering insights into reproductive strategies and evolutionary adaptations of bot flies.

摘要: Emitting alarm calls may be costly, but few studies have asked whether calling increases a caller's risk of predation and survival. Since observing animals calling and being killed is relatively rare, we capitalized on over 24,000 h of observations of marmot colonies and asked whether variation in the rate that yellow-bellied marmots (Marmota flaviventer) alarm called was associated with the probability of summer mortality, a proxy for predation. Using a generalized mixed model that controlled for factors that influenced the likelihood of survival, we found that marmots who called at higher rates were substantially more likely to die over the summer. Because virtually all summer mortality is due to predation, these results suggest that calling is indeed costly for marmots. Additionally, the results from a Cox survival analysis showed that marmots that called more lived significantly shorter lives. Prior studies have shown that marmots reduce the risk by emitting calls only when close to their burrows, but this newly quantified survival cost suggests a constraint on eliminating risks. Quantifying the cost of alarm calling using a similar approach in other systems will help us better understand its true costs, which is an essential value for theoretical models of calling and social behavior.

摘要: Dispersal is an important life history trait with significant consequences for spatially structured populations, as the exchange of individuals between habitat patches is crucial for maintaining metapopulation connectivity. In this study, we used a long-term data set (2005-2023) to describe dispersal patterns in a patchy population of the Western Yellow Wagtail Motacilla flava within a large (approximately 1,300 km2) study area in the boreal zone of European Russia. We quantified dispersal distances for birds that dispersed outside their natal or breeding habitat patches and applied a multistate capture-recapture approach to estimate natal and breeding dispersal probabilities. Of 395 adult wagtails and 1,610 nestlings ringed, 3% of birds ringed as adults and 3% of birds ringed as nestlings were resighted outside their natal or breeding patches. The probability of natal dispersal (0.29 +/- 0.05) was significantly higher than the probability of breeding dispersal (0.05 +/- 0.01). The median natal dispersal distances (2.8 km for males, 3.9 km for females) were the same as the median breeding dispersal distances (2.7 km for males, 3.9 km for females). We did not find a significant effect of the fledging date on either the natal dispersal distance or the natal dispersal probability. Similarly, we did not find a significant effect of the previous reproductive success on either the breeding dispersal distance or the breeding dispersal probability. Our results indicate that strong breeding site fidelity and short-distance natal dispersal are the dominant dispersal strategies in a patchy population of the western yellow wagtail.

摘要: Climate change and its resulting effects on seasonality are known to alter a variety of animal behaviors including those related to foraging, phenology, and migration. Although many studies focus on the impacts of phenological changes on physiology or fitness enhancing behaviors, fewer have investigated the relationship between variation in weather and phenology on risk assessment. Fleeing from predators is an economic decision that incurs costs and benefits. As environmental conditions change, animals may face additional stressors that affect their decision to flee and influence their ability to effectively assess risk. Flight initiation distance (FID)-the distance at which animals move away from threats-is often used to study risk assessment. FID varies due to both internal and external biotic and physical factors as well as anthropogenic activities. We asked whether variation in weather and phenology is associated with risk-taking in a population of yellow-bellied marmots (Marmota flaviventer). As the air temperature increased marmots tolerated closer approaches, suggesting that they either perceived less risk or that their response to a threat was thermally compromised. The effect of temperature was relatively small and was largely dependent upon having a larger range in the full data set that permitted us to detect it. We found no effects of either the date that snow disappeared or July precipitation on marmot FID. As global temperatures continue to rise, rainfall varies more and drought becomes more common, understanding climate-related changes in how animals assess risk should be used to inform population viability models.

摘要: Non-signaling functions of coloration include thermoregulation (thermal melanism hypothesis), protection against ultraviolet radiation (photo- protection hypothesis), and concealment from predators (crypsis hypothesis). We investigated whether dorsal coloration in 19 populations of spiny-footed lizards, Acanthodactylus erythrurus, across the Iberian Peninsula varies according to these functions. We captured adult males and females in each population and calculated standardized dorsum brightness estimates from photographs. We also calculated standardized ground luminosity estimates and gathered information on latitude, altitude, mean annual temperature, and mean annual solar radiation for each location. Males showed a higher percentage of black coloration and a more contrasted dorsum than females, suggesting different selection pressures on dorsal coloration in both sexes. Furthermore, males showed a darker dorsum and a higher percentage of black coloration at higher altitudes and when the ground was darker. In contrast, females exhibited a darker dorsum only when the ground was darker and a higher percentage of black coloration only at higher altitudes. We also observed that the variation of dorsum luminosity within males and the variation of dorsum luminosity among females within populations were both positively related to the variation of ground luminosity among different points within locations. Latitude, temperature, and solar radiation were not significantly related to dorsal coloration in either sex. Our results support the photoprotection and crypsis hypotheses in males and, to some extent, in females, whereas the thermal melanism hypothesis is weakly supported in both sexes. These findings suggest that there is local adaptation in the dorsal coloration of the spiny-footed lizard.

摘要: Alarm calls in bird vocalizations serve as acoustic signals announcing danger. Owing to the convergent evolution of alarm calls, some bird species can benefit from eavesdropping on certain parameters of alarm calls of other species. Vocal mimicry, displayed by many bird species, aids defense against predators and may help brood parasites during parasitism. In the coevolutionary dynamics between brood parasites, such as the common cuckoo ( Cuculus canorus), and their hosts, female cuckoo vocalizations can induce hosts to leave the nest, increasing the probability of successful parasitism and reducing the risk of host attacks. Such cuckoo calls were thought to mimic those of the sparrowhawk. However, owing to their similarity to alarm calls, we propose a new hypothesis: Female cuckoos cheat their hosts by mimicking the parameters of the host alarm call. In this study, we tested this new hypothesis and the sparrowhawk mimicry hypothesis simultaneously by manipulating the syllable rate in male and female common cuckoo vocalizations and playing them in front of the host Oriental reed warbler ( Acrocephalus orientalis) for examination. The results indicate that similar to a normal female cuckoo call, a female call with a reduced syllable rate prompted the hosts to leave their nests more frequently and rapidly than male cuckoo calls. Additionally, the male cuckoo calls with increased syllable rate did not prompt the host to leave their nests more frequently or quickly compared with the male cuckoo calls with a normal syllable rate. Our results further confirm that female common cuckoos mimic the vocalizations of Eurasian sparrowhawks ( Accipiter nisus), reveal the function mechanisms underlying such mimicry, and support the theory of imperfect mimicry.

摘要: The microbiome of mammals has profound effects on host fitness, but the process, which drives the assembly and shift of mammalian micro- biome remains poorly understood. To explore the patterns of small mammal microbial communities across host species and geographical sites and measure the relative contributions of different processes in driving assembly patterns, 2 sympatric desert rodent species ( Dipus sagitta and Meriones meridianus) were sampled from 2 geographically distant regions, which differed in the environment, followed by 16S rRNA gene sequencing. The microbiomes differed significantly between D. sagitta and M. meridianus, and linear mixed modeling (LMM) analysis revealed that microbial diversity was mostly affected by species rather than the environment. For each rodent species, the microbiome diversity and structure differed across geographical regions, with individuals from lower rainfall environments exhibiting greater diversity. The null modeling results suggested dispersal limitation and ecological drift rather than differential selective pressures acting on the microbiome. In addition, each group had a different core genus, suggesting that the taxonomic composition of the microbiome was shaped most strongly by stochastic processes. Our results suggest that variation in the microbiome between hosts, both within and among geographic rodent populations, is driven by bacterial dispersal and ecological drift rather than by differential selective pressures.These results elucidated the diversity patterns and assembly processes of bacterial microbiomes in small desert mammals. Deciphering the processes shaping the assembly of the microbial community is a premise for better understanding how the environment-host-microbe interactions of mammals are established and maintained, particularly in the context of increased environmental disturbances and global changes.

摘要: Vocal individuality is essential for social discrimination but has been poorly studied in animals that produce communal signals (duets or choruses). Song overlapping and temporal coordination make the assessment of individuality in communal signals more complex. In addition, selection may favor the accurate identification of pairs over individuals by receivers in year-round territorial species with duetting and long-term pair bonding. Here, we studied pair and individual vocal signatures in the polyphonal duets of rufous horneros Furnarius rufus, a Neotropical bird known for its long-term pair bonds. Hornero partners engage in duets to deter territorial intruders and protect their partnership year-round and can discern duets from neighbors versus strangers. Using a dataset of 471 duets from 43 pairs in 2 populations, we measured fine-scale acoustic features across different duet levels (e.g., complete duets to non-overlapping syllable parts) and analysis levels (pair or individual). Permuted linear discriminant function analyses classified pairs and individuals more accurately than expected by chance (means: 45% and 47% vs. 4 and 2%). Pair identity explained more variance in the multivariate acoustic features of duets than individual or population identities. The initial frequency of the duet showed strong potential for encoding pair identity.The acoustic traits contributing most to individual vocal signatures varied between sexes, which might facilitate the simultaneous assessment of duetters' identities by receivers. Our study indicates that vocal individuality may exist even in species with intricate and innate communal signals and elucidates the mechanisms employed by horneros in their social discrimination ability.

摘要: The study of temperament and behavioral syndromes in insects is still in its early stage, and research conducted to date has mainly focused on locomotor activity and thanatosis. Dung beetles have been the subject of extensive behavioral studies; however, very few studies have addressed the expression of temperament. Those doing so only looked at subsocial and sexual horn dimorphic species, suggesting subsociality and/or sexual horn-dimorphism as possible facilitators of temperament expression. To test this assumption, we conducted a temperament study in a hornless, non-subsocial species, namely Geotrupes mutator (Marsham, 1802). We set up laboratory tests to evaluate 3 behaviors (activity, thanatosis, and distress calls) through the measurement of 7 distinct behavioral traits (3 activity-, 1 thanatosis-, and 3 call-related traits). We found high levels of individual repeatability in all activity- and thanatosis-related traits. We also identified behavioral differences between individuals, which may reflect differences in temperament. Statistical analyses revealed a negative correlation between activity and thanatosis. These results show that the temperament and behavioral syndromes related to activity and thanatosis may also be expressed in dung beetle species that are neither subsocial nor sexual horn dimorphic. By contrast, we only found one of 3 sound-related traits tested (frequency) to be clearly repeatable. Males and females presented a different structure of the stridulatory apparatus, suggesting that morphology may affect the frequency of sounds emitted.These results indicate that certain sound traits might not be good descriptors of individual temperament revealing the need for future research addressing the role of bioacoustics.

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