Biology subjects

Safian, S.

Publications and source records attributed to Safian, S..

4 recordsLinked to original sources

bioRxiv2025

Elevational patterns in two groups of micromoths (Lepidoptera: Pterophoridae, Alucitidae) in tropical forests of Mount Cameroon

Tropical elevational gradients offer unique insights into ecological processes shaping biodiversity, although micromoths remain severely understudied, especially in the Afrotropics. We analysed species richness, community composition, and functional traits (elevational range size and wingspan) of two micromoth families, many-plumed moths (Alucitidae) and plume moths (Pterophoridae), along a complete forest gradient on Mount Cameroon, an Afrotropical biodiversity hotspot. Alucitidae exhibited a distinct mid-elevation diversity peak, mirroring common patterns in tropical butterflies and moths, whereas Pterophoridae showed an uncommon upslope increase in species richness. Both families demonstrated clear elevational turnover in community composition, indicative of strong environmental filtering. Additionally, community-weighted elevational range size and wingspan increased consistently with elevation, supporting Rapoports rule and Bergmanns cline, respectively. These patterns likely reflect interactions among climatic factors and environmental complexity, though the underlying mechanisms remain unresolved. Our findings reveal the unique communities of both mid- and high-elevation forests, as well as the distinctiveness of species-poor lowland assemblages. This elevational differentiation underscores the need for conservation across the full gradient and the vulnerability of endemic highland taxa to climate-driven range contractions. Comprehensive research on neglected tropical insect groups is urgently needed to better anticipate biodiversity responses to environmental change.

ecology↗

bioRxiv2025

Butterfly and moth habitat specialisation changes along an elevational gradient of tropical forests on Mount Cameroon

Niche breadth is a key ecological trait influencing species distribution, persistence, vulnerability to environmental change, and interspecific interactions. While the elevational niche-breadth hypothesis predicts broader ecological niches at higher elevations due to increased environmental stress and heterogeneity, empirical tests have mostly focused on food specialisation, with habitat specialisation remaining largely overlooked. Here, we provide the first direct test of this hypothesis using habitat characteristics, analysing fruit-feeding butterflies and moths along a complete tropical forest gradient on Mount Cameroon. We quantified habitat-related niche breadth using the Outlying Mean Index across 96 forest plots spanning 350-2200 m a.s.l., employing two complementary metrics: absolute niche breadth (ANB) based on the total range of habitat conditions occupied across the gradient, and within-elevation niche breadth (WENB) reflecting the proportion of local habitat heterogeneity utilized at each elevation. Forest structural heterogeneity increased steeply with elevation. In response, butterfly communities showed a substantial upslope broadening of ANB, particularly in Charaxinae and Satyrinae. Moth families exhibited similar but weaker patterns. In contrast, WENB showed no consistent elevational patterns and was more variable among lepidopteran groups. These results support the elevational niche-breadth hypothesis for habitat specialisation in tropical butterflies, likely reflecting increased habitat opportunity space and reduced competition at higher elevations. However, the decoupling of ANB and WENB highlights that broader availability of environmental conditions does not necessarily translate into more generalised local habitat use, suggesting constraints from behavioural preferences, resource distributions, or biotic interactions. By disentangling overall and local habitat niche breadths, our study reveals unrecognised complexity in elevational specialisation patterns and provides new insights into how tropical insect respond to environmental gradients.

ecology↗

bioRxiv2022

Diversification is correlated with temperature in white and sulfur butterflies

Temperature is thought to be a key variable explaining global patterns of species richness. However, to investigate this relationship carefully, it is necessary to study clades with broad geographic ranges that are comprised of species inhabiting diverse biomes with well- characterized species ranges. In the present study, we investigate the link between temperature and diversification in the butterfly family Pieridae (sulfurs and whites) by combining Next Generation sequences and published molecular data with fine-grained distribution information. After building the most comprehensive phylogeny of the group, with almost 600 species and all higher taxa (subfamilies, tribes and subtribes), we found strong support for the following relationships within the family: Dismorphiinae + (Coliadinae + (Pseudopontiinae + Pierinae)). With a curated distribution dataset of over 800,000 occurrences, we conducted multiple comparative phylogenetic analyses that provided strong evidence that species in environments with more stable daily temperatures or with cooler maximum temperatures in the warm seasons have higher diversification rates. We also found a positive correlation between speciation and extinction with paleotemperature: as global temperature decreased through geological time, so did diversification rates. Although many studies demonstrate higher diversity in the tropics, we have been able to identify specific climate variables associated with changes in diversification, while also inferring the most robust and well sampled phylogenomic framework for Pieridae to date.

evolutionary biology↗

bioRxiv2021

Role and patterns of butterflies and hawkmoths in plant-pollinator networks at different elevations and seasons in tropical rainforests of Mount Cameroon

O_LIButterflies and moths are well-visible flower visitors. Nevertheless, almost no quantification of their role in plant-pollinator interactions exists at a community level, especially from tropical rainforests. Moreover, we have virtually no knowledge on environmental and other factors affecting lepidopteran flower visits. C_LIO_LIWe focused on the role of butterflies and hawkmoths as flower visitors in tropical rainforests of Mount Cameroon, especially on its elevational and seasonal changes. We also analysed their preferences to selected floral traits, with a specific focus on pollination syndromes. C_LIO_LIWe video-recorded flower visitors of 1,115 specimens of 212 plant species (>26,000 recording hrs) along the complete elevational gradient of rainforests in two main seasons, and compared frequencies of flower-visiting lepidopterans to other visitors. We compared characteristics of plant-lepidopteran networks among elevations and seasons, and analysed patterns of selected lepidopteran traits. Finally, we analysed inter-family differences in their floral preferences. C_LIO_LIAltogether, we recorded 734 flower visits by 80 butterflies and 27 hawkmoth species, representing only ~4% of all 18,439 flower visits. Although lepidopterans visited only a third species, they appeared key visitors of several plants. The most flower visits by lepidopterans were recorded in mid-elevations and dry season, mirroring the general patterns of lepidopteran diversity. The networks showed no apparent elevational or seasonal patterns, probably because of the surprisingly high specialisation of interactions in all networks. Significant non-linear changes of proboscis and forewing lengths were found along elevation, and long-proboscid hesperiid butterflies visited flowers with longer tubes or spurs. Substantial differences in floral preferences were found between sphingids, and papilionid, nymphalid and lycaenid butterflies, revealing importance of nectar production, floral size and shape for sphingids, and floral colour for butterflies. C_LIO_LIButterflies and hawkmoths were confirmed as relatively minor visitors of tropical forest flowers, although they seemed crucial for pollination of some plant species. Moreover, the revealed floral preferences and trait-matchings confirmed a potential of some lepidopteran families to drive floral evolution in tropical ecosystems. C_LI

ecology↗