How carnivores time their road use relative to vehicles in African conservation areas remains poorly understood. We examined the on-road activity of leopard (Panthera pardus) and black-backed jackal (Lupulella mesomelas) relative to vehicles at three South African conservation properties spanning a 24-fold range in vehicle activity, with blue wildebeest (Connochaetes taurinus) as a diurnal comparator. Wildebeest tracked diurnal vehicle activity at every property, whereas both carnivores were most active when vehicles were scarce and overlapped vehicle activity far less than the comparator. Jackal overlap was lowest at the property with the heaviest traffic. Leopards overlapped vehicles less than jackals where traffic was lighter, but this reversed where traffic was heaviest, a descriptive pattern we did not test. Neither carnivore appeared later than expected after vehicle passages where records sufficed for the test, mainly at the heaviest-traffic property, so we found no evidence of an immediate response to vehicles. The only fine-scale signal was the expected aggregation of the comparator. Because both carnivores are naturally nocturnal, their low daytime overlap with vehicles is consistent with, but not evidence of, avoidance. Road use relative to vehicles differed between species and among sites and was not a simple function of traffic volume.
Alternative reproductive tactics (ARTs) are differences in reproductive behaviour among individuals of the same sex that maximise fitness and may increase phenotypic variation. A common pattern among bats involves two main ARTs: territorial (T) males defend roost sites to secure mating, limiting their range to areas near their roosts. Non-territorial (NT) males mate opportunistically and forage in areas distant from the roost, alongside females. We tested the prediction that variation in wing morphology among NT and T males would reflect these functional demands. We measured 491 Carollia perspicillata individuals (F = 286, T = 49, NT = 156) monitored between 2016 and 2025. Our results confirmed differences in roost activity among ARTs and showed that T males had the highest wing loading (WL) and a smaller, more constrained distribution in the wing morphospace defined by aspect ratio (AR) and WL. In contrast, NT males and females showed considerable similarity in trait distributions. These results suggest an association between wing morphology and ART behaviour, with consequences for flight performance. Territorial male morphologies favour agile, short-distance, fast flights in cluttered environments, whereas NT male and female morphologies favour slower, less costly long-distance flights. The rigorous functional demands associated with T male flight patterns are likely to constrain their occupation of morphological space. This study provides the first evidence of ART-dependent intrasexual morphological variation in bat wing shape.
Island endemic species are highly sensitive to various pressures due to small population sizes and adaptations to specific island conditions. This makes them more threatened than mainland species. On the other hand, conservation actions aimed at improving their population status may be more effective because threats can be more readily controlled within the limited area of the island. If effective, population trends in species benefiting from conservation efforts should be more positive than in those not targeted by such actions. We tested this prediction using island-endemic avian species in the order Charadriiformes, a highly threatened group of waders, gulls and their relatives, drawing on literature information on their global population trends and conservation actions undertaken, recognising five main action types (area protection, predator control, species protection, translocation, resource enhancement). Our models showed a higher probability of negative population trends in species whose ranges are within protected areas than in those occurring outside them. This pattern may reflect the designation effect, i.e. the tendency for protected areas to be established specifically for species with an unfavourable conservation status. Alternatively, protected areas may be unable to secure these species due to limited capacity to mitigate the major threats they face.
The key event in incipient speciation is the emergence of reproductive isolation between diverging populations. Reproductive isolation can occur before or after fertilisation. Postmating prezygotic isolation, or gametic isolation, occurs between insemination and fertilisation and may drive late stages of speciation. This study evaluates gametic isolation in subspecies of the house mouse (Mus musculus musculus-Mmm, M. m. domesticus-Mmd) and a more phylogenetically distant species, M. spretus (Msp). Using an in vitro sperm-ovum binding assay, we quantified sperm-ovum binding in reciprocal crosses among four wild-derived Mmm strains, three Mmd strains, and one Msp strain. Results showed that sperm did not preferentially bind to conspecific ova, but binding rates varied. Mmm sperm bound the fewest ova, followed by Mmd, whereas Msp sperm bound the most, regardless of the origin of the ova. Thus, under standardised in vitro conditions, we detected no evidence for species-specific sperm-ovum binding among the taxa studied. Instead, variation in sperm binding rate may reflect temporal changes in sperm longevity and/or differences in mating-system promiscuity among species, with Msp being the most promiscuous.
Information on mating and reproductive behaviour in wild mustelids remains limited and is almost exclusively based on captive studies. The same is true for the steppe polecat (Mustela eversmanii), a particularly elusive species that is endangered in Europe. In the Czech Republic, we used camera traps to capture steppe polecats mating in the wild, documenting the sequence in detail. The footage revealed previously undescribed male behaviours, including long-term den monitoring, burrow modification, and provisioning of nesting material. Copulation began at approximately 07:00, during daylight, above ground, with several mating bouts, the longest recorded lasting at least 21 min. After copulation, the male guarded the female for more than one and a half hours, repeatedly preventing her from leaving the burrow area. These observations are consistent with patterns described in captivity but substantially extend our existing knowledge by documenting complex pre- and post-copulatory behaviour under natural conditions.
