Abstract Biotic factors (e.g., maternal age) and abiotic factors (e.g., weather) play vital roles in reproduction. However, there is little information about the combined effects of maternal age and weather on the reproductive output of cultured Asian yellow pond turtles, Mauremys mutica. To address this issue, we surveyed and compared the reproductive output of 13-year-old and 25-year-old female turtles on non-rainy and rainy days. The results showed that older females produced larger eggs than younger females regardless of the weather conditions. Females laid larger clutch sizes (number of eggs per nest) under non-rainy conditions compared with those under rainy conditions. However, the variation in clutch frequency (number of clutches per day) was independent of maternal age and weather. There was no effect of an interaction between maternal age and weather on egg mass, clutch size or clutch frequency. Our results suggest that maternal age and weather had significant effects on egg mass and clutch size, respectively. These results imply that maternal age, together with weather conditions (mainly conditions of rain), can affect the reproductive output of M. mutica. Our results provide useful information for the artificial breeding and stock management of M. mutica.

Abstract Islands are ideal settings for the study of evolution, ecology and genetic diversity. The tree sparrow (Passer montanus), which is distributed both inside and outside the Sichuan Basin and is relatively easy to capture, was used as our study species to test whether any genetic differences exist between within and outside of the Sichuan Basin. We analyzed mitochondrial and nuclear gene sequence variations to illustrate the continental island effect within the Sichuan Basin. Overall, fragments from four mtDNA and one nuclear sequence (Cytb + COI + 12S rRNA + Dloop + Myo) were amplified, with the concatenated alignment comprising 3234 bp. The results of Bayesian and maximum parsimony trees indicated two major branches, one of which is composed mainly of populations within the Sichuan Basin, while the other comprised populations distributed in the surrounding mountains. The population in Sichuan Basin was more basal than that in the surrounding mountains. The genetic distance between inner and outer populations was 0.095 and genetic differentiation index (FST) between inner and outer populations was 0.342. This study shows that the overall distribution pattern of tree sparrow populations in the Sichuan Basin and its surrounding mountains is probably the result of a vicariance event due to spatial isolation.

Abstract Remating rate is a fundamental parameter that acts on disease transmission, sexual dimorphism, and the rate of evolution of species. Recent studies have indicated that sperm production can be costly. It is thus likely that males may tailor their sperm expenditure according to female mating status and the remating interval between successive matings. In this study, we investigated the effects of male remating interval, female mating status and familiarity of females in the ladybird beetle Propylea dissecta (Mulsant). Ten-day-old adults were allowed to mate and, post disengagement, these adults were exposed to second mating opportunities, either immediately after the first mating, or 6, 18 or 24 h later. To assess the effect of female mating status, the males were subjected to mating with virgin and mated females. Similarly, for assessing the effects of female familiarity, males were subjected to mating with either familiar or unfamiliar females. With increasing remating interval individuals mated for longer, resulting in higher fecundity. Percent egg viability increased with increased remating interval and was highest at 24 h. Mated and unfamiliar females were found to be more fecund than virgin females. Mated females produced a higher number of viable eggs than virgins, suggesting that multiple mating and promiscuity are essential for maximizing the reproductive success of both sexes.

Abstract Organisms living in extreme environments, such as amphibians inhabiting the Tibetan plateau, are faced with a magnitude of potentially strong selection pressures. With an average elevation exceeding 4500 m, the Tibetan plateau is mainly characterized by low temperatures, but little is known about the influence of this factor on the growth, development, and behaviour of amphibian larvae living in this environment. Using a common garden experiment, we studied the influence of temperatures on the early growth and development of tadpoles of the Tibetan brown frog (Rana kukunoris) endemic to the eastern Tibetan plateau. We discovered that temperature had a significant influence on early growth and development of the tadpoles, with those undergoing high-temperature treatment growing and developing faster than their siblings from a low-temperature treatment. However, high-altitude individuals grew faster than low-altitude individuals at low temperatures, while the opposite was true at high temperatures. These results support the temperature adaptation hypothesis, as tadpoles’ growth and developmental rates were maximized at the temperatures experienced in their native environments. These results suggest that variation in ambient temperature, combined with evolutionary adaptation to temperature of local environments, is probably one of the most critical environmental factors shaping altitudinal differences in the growth and development of amphibian larvae on the Tibetan plateau.

Abstract Most plant species in the Atlantic Forest invest in zoochory as a dispersal mechanism and many depend on vertebrates to fulfill that role. The sizes of fruits and seeds are limiting factors in interactions between vertebrates and plant species. For example, plants that produce fruits with large seeds are more dependent on large frugivorous vertebrates for dispersal. We used camera traps to observe the interactions between frugivorous vertebrates and two large seed-producing plants of the genusSpondiasin the Tableland of the Atlantic Forest of Espírito Santo, Brazil. Between 2015 and 2016 (622 camera days), we recorded 17 species of frugivorous vertebrates potentially ingesting fruit at the studied sites. Among the species recorded, only the lowland tapir (Tapirus terrestris) was observed interacting directly withS. venulosaandS. macrocarpa. Our analysis indicates that the type of interaction depends on the body size of the vertebrate species, meaning that direct interaction with fruits ofSpondiasis commonly performed by medium and large vertebrates, such as spotted pacas, agoutis, and tapirs. Our study highlights the importance of these vertebrates in the forest remnants of the Atlantic Forest Tableland, such as the Linhares-Sooretama forest complex, for conservation and regeneration of plant communities.

Abstract When a species often experiences variation in its environmental conditions, metabolic flexibility is required. We studied the duration of the digestive cycle and the activity of key digestive enzymes (proteolytic, amylase, lipase) at short and long times after feeding in the hepatopancreas of the osmoregulator crab Neohelice granulata from the Mar Chiquita coastal lagoon (Buenos Aires Province, Argentina). We compared these responses upon hyper-regulation and under osmoconformation conditions (10 and 35 psu). The results show the ability of this crab to hyper-regulate in different feeding states. No significant differences were observed in the duration pattern of the digestive cycle between hyper-regulation and osmoconformity. However, distinct responses after feeding were observed in the activities of the digestive enzymes studied in relation to the osmoregulatory state. In individuals exposed to 35 psu, proteolytic activity was higher at 8 h and remained constant until 72 h after feeding. At 10 psu, this activity was higher at 48 h after feeding than before feeding. At 35 psu, the amylase activity after feeding was greater than the prefeeding activity. No differences were observed in the activity of lipase at 35 psu, but at 10 psu this activity was lower 1 h after feeding than before feeding. This work constitutes a contribution to our knowledge of the physiology of crustaceans and attempts to clarify the possible mechanisms of digestive settings associated with hyper-regulation.

Abstract Selection pressure is an important force in shaping the evolution of vertebrate brain size among populations within species as well as between species. The evolution of brain size is tightly linked to natural and sexual selection, and life-history traits. In particular, increased environmental stress, intensity of sexual selection, and slower life history usually result in enlarged brains. However, although previous studies have addressed the causes of brain size evolution, no systematic reviews have been conducted to explain brain size in anurans. Here, we review whether brain size evolution supports the cognitive buffer hypothesis (CBH), the expensive tissue hypothesis (ETH), or the developmental cost hypothesis (DCH) by analyzing the intraspecific and/or interspecific patterns in brain size and brain regions (i.e., olfactory nerves, olfactory bulbs, telencephalon, optic tectum, and cerebellum) associated with ecological factors (habitat, diet and predator risk), sexual selection intensity, life-history traits (age at sexual maturity, mean age, longevity, clutch size and egg size, testis size and sperm length), and other energetic organs. Our findings suggest that brain size evolution in anurans supports the CBH, ETH or DCH. We also suggest future directions for studying the relationships between brain size evolution and crypsis (i.e., ordinary mucous glands in the skin), and food alteration in different developmental stages.

Abstract Because temperature strongly influences biological processes of ectotherms, it also plays a fundamental role in determining their geographical distribution. We evaluated the low-temperature tolerance of early juveniles of six terrestrial hermit crab species in the family Coenobitidae (genera Birgus and Coenobita), B. latro, C. brevimanus, C. cavipes, C. purpureus, C. rugosus, and C. violascens that occur in the northwestern Pacific region, Japan. A total of 30 laboratory-raised juveniles (about 1 mm in shield length) carrying gastropod shells were individually stocked in small plastic cups with sandy bottoms in temperature-controlled incubatory chambers at ∼27°C. The temperature was reduced by 1°C every 48 h, and the juveniles were observed until all the crabs had died; the median lethal temperature (MLT) was estimated as the temperature at which 50% of the test juveniles had died. The MLT estimates varied significantly among the species, and the most northward distributed species, C. purpureus, had the lowest MLT values. The phylogeny, paleoceanography, paleogeography, and paleoclimatology suggest that cooler thermal regimes might have acted as an evolutionary force for the divergence of C. purpureus in the Pliocene. A negative correlation was found between the northern latitudinal limit of distribution and the MLT values, even after controlling for the phylogenetic relationships in the six coenobitids. A temperature-dependent biogeography was thus recognized in terrestrial hermit crab species in the northwestern Pacific region, and global warming is expected to affect their geographical distributions.

Abstract Sexual size and shape dimorphism (SSD and SShD) are understudied phenomena in millipedes. In the present study, we investigated both kinds of sexual dimorphism in some morphological traits, as well as whether shape of the morphological traits varied more than their size. Three julidan species, viz., Pachyiulus hungaricus (Karsch, 1881), Megaphyllum unilineatum (C.L. Koch, 1838), and M. bosniense (Verhoeff, 1897), were used for these purposes. By means of traditional and geometric morphometrics, we found that SSD exists in linear measurements of the tested morphological traits, as well as SShD of the legs in all analysed species. Also, SSD of antennal centroid size was detected in P. hungaricus and M. unilineatum, in addition to SShD of antennae in P. hungaricus and M. bosniense. Our results indicate that morphological intersexual differences are species-specific and that the shape of some morphological traits varies more than the size of centroids of the same structures.

Abstract Evolution acts through a combination of four different drivers: (1) mutation, (2) selection, (3) genetic drift, and (4) developmental constraints. There is a tendency among some biologists to frame evolution as the sole result of natural selection, and this tendency is reinforced by many popular texts. “The Naked Ape” by Desmond Morris, published 50 years ago, is no exception. In this paper I argue that evolutionary biology is much richer than natural selection alone. I illustrate this by reconstructing the evolutionary history of five different organs of the human body: foot, pelvis, scrotum, hand and brain. Factors like developmental tinkering, by-product evolution, exaptation and heterochrony are powerful forces for body-plan innovations and the appearance of such innovations in human ancestors does not always require an adaptive explanation. While Morris explained the lack of body hair in the human species by sexual selection, I argue that molecular tinkering of regulatory genes expressed in the brain, followed by positive selection for neotenic features, may have been the driving factor, with loss of body hair as a secondary consequence.