Biology subjects

Segami, J. C.

Publications and source records attributed to Segami, J. C..

3 recordsLinked to original sources

bioRxiv2026

Predation of small nocturnal primates (Microcebus) on Madagascar; insights into predator preferences in Andohahela National Park

Predation is a major selective force shaping lemur behaviour and population dynamics, yet direct observations remain rare, particularly for small nocturnal species. Here, we document predation on mouse lemurs (Microcebus spp., Cheirogaleidae) in Andohahela National Park, south-eastern Madagascar, and using complementary evidence from radio-telemetry and owl pellet analyses. Two radio-collared individuals were confirmed as prey of endemic snakes, Ithycyphus oursi and Madagascarophis meridionalis (both Pseudoxyrhophiidae), representing the first documented records of Microcebus predation by these species. Examination of owl pellets and prey remains from three sites and from three owl species revealed a single predation event by Asio madagascariensis (Strigidae), likely involving M. tanosi, no evidence of mouse lemur predation by Tyto alba (Tytonidae) despite high local prey availability, and a single and first predation record from Athene superciliaris (Strigidae). Material from A. superciliaris roosts was otherwise dominated by invertebrates, indicating that primate predation is likely opportunistic. Together, these findings expand the known predator guild of mouse lemurs and suggest that snake predation is rarely detected, and its contribution to mouse lemur mortality and population dynamics is likely underestimated. Our findings demonstrate how combining behavioural field observations with dietary evidence can uncover otherwise undetected predation events and clarify predator prey relationships in nocturnal primates.

ecology↗

bioRxiv2026

Diet and feeding strategies of two sympatric mouse lemurs (Microcebus) in the xeric forests of Andohahela, southeastern Madagascar

Understanding how closely related species coexist in highly seasonal and unpredictable environments is central to studies of ecological differentiation and niche partitioning. We investigated the feeding ecology of sympatric populations of Microcebus murinus and M. griseorufus within a contact zone in Andohahela National Park, southeastern Madagascar, across dry and wet seasons. Using a combination of direct behavioral observations (1,611 feeding records), fecal sample analyses (n = 56), and vegetation phenology surveys, we quantified dietary composition, seasonal shifts in resource use, and habitat-related variation. Seasonal changes in diet were pronounced, with dry-season feeding dominated by exudates and wet-season diets incorporating greater proportions of fruit and flowers, closely tracking phenological patterns at both sites. Diets of both species were dominated by plant resources, but consistent interspecific differences in dietary strategy were evident. Although both species consumed comparable proportions of insect prey, M. murinus showed pronounced wet-season increases in the use of high-sugar, carbohydrate-rich floral resources (15.9%) and hemipteran-associated honeydew (30.6%). In contrast, M. griseorufus relied more consistently on predictable exudates throughout the year. Fecal analyses supported observational data but revealed differences in the detectability of dietary components, with increased representation of invertebrates in the wet season and seeds in the dry season. These results indicate substantial dietary overlap but consistent differences in resource use, suggesting that coexistence is facilitated by fine-scale trophic differentiation within a broadly shared omnivorous niche. Such subtle but persistent differences in feeding strategy likely reduce competitive overlap and enable continued sympatry in a climatically variable and resource-limited system.

ecology↗

bioRxiv2025

Programmed DNA elimination drives rapid genomic innovation in two thirds of all bird species

Bird genomes are among the most stable in terms of synteny and gene content across vertebrates. However, germline-restricted chromosomes (GRCs) represent a striking exception where programmed DNA elimination confines large-scale genomic changes to the germline. GRCs are known to occur in songbirds (oscines), but have been studied only in a few species of Passerides such as the zebra finch, the key model for passerine genomics. Their presence and evolutionary dynamics in most major passerine lineages remain largely unexplored, with suboscines entirely unexamined by cytogenetic or genomic methods. Here, we present the most comprehensive comparative analysis of GRCs to date, spanning 44 million years of passerine evolution. By generating the first germline reference genomes of an oscine and a suboscine, 22 novel germline draft genomes spanning nearly all major passerine lineages and a germline draft genome of a parrot outgroup, we show that the GRC is likely present in 6,700 passerine species. Our results reveal that the GRC evolves rapidly and distinctly from the standard A chromosomes (autosomes and sex chromosomes), yet retains functionally important, selectively maintained genes. We observed gene and repeat turnover occuring orders of magnitude faster than on the A chromosomes. Some GRC genes, such as cpeb1 and pim1, are widespread from an ancient duplication. In contrast, other GRC genes, like mfsd2b and bmp15, have been independently duplicated onto the GRC multiple times, suggesting adaptive constraints. The discovery of zglp1 on the zebra finch GRC, initially copied from chromosome 30 and subsequently lost from it, indicates functional replacement, where the GRC permits gene loss from the standard genome. As the GRC harbors the only zglp1 copy in most of the [~]4000 Passerides species, GRC loss would compromise essential germline functions. Our findings establish the GRC as a genomic innovator driving rapid germline evolution. This fact highlights its evolutionary significance for passerine diversification and suggests that programmed DNA elimination may be an overlooked yet phylogenetically widespread mechanism in many understudied animal lineages.

genomics↗