Biology subjects

Beenaerts, N.

Publications and source records attributed to Beenaerts, N..

4 recordsLinked to original sources

bioRxiv2026

Pigments and microstructure of the colour polymorphic shells of Polymita picta and P. muscarum (Gastropoda: Cepolidae), with observations on a new light-transmitting shell spot system

Colour polymorphism in the Cuban painted snails Polymita picta and P. muscarum is striking, yet the pigmentary and structural bases remain unclear. We combined spectrophotometric screening, Raman micro-spectroscopy, scanning electron microscopy (SEM) and LED transillumination to link pigments, ultrastructure and optics across shell morphs. A Sepia officinalis melanin standard yielded a robust linear calibration used to quantify total melanin pigments at 215 nm in pooled extracts. Melanin was detected in all samples with predominance in darker morphs. Raman spectra (785 nm) confirmed aragonite mineral organization and revealed carotenoid bands, consistent with a mixed-pigment model in which carotenoids contribute to ground and band colours and melanins underlie darker elements. SEM showed a canonical crossed-lamellar layer with alternating transverse and co-marginal layers. At shell spot areas, shell surfaces were cribose; fracturing shells near such spots showed a locally disordered, more porous mineral arrangement enriched in organic matrix, bounded basally by an organic layer. Under transillumination, these spots acted as discrete light-transmitting windows, abundantly in P. muscarum and also sparsely in P. picta; as the spots appear only as pigmented dots but also transmit light, we refer to them as cryptotransmissive domains, which is apparently a novel finding in terrestrial gastropods. We speculate that these may represent a pigment-structure-optics framework in which pigments and microstructural packing jointly play potential roles in photoprotection and behavioural thermoregulation. These results provide a mechanistic context for colour polymorphism in Polymita and suggest testable links to thermal ecology and conservation.

zoology↗

bioRxiv2026

Genome-wide identification of heat shock proteins (HSP70) in the Cuban painted snail Polymita picta: evolutionary constraints face climate change challenges

Climate change poses a critical threat for biodiversity. Among ectothermal animals, terrestrial molluscs are considered highly vulnerable to temperature increase and drought due to their low vagility and specialized ecological requirements. In response to thermal stress, heat shock proteins (HSP70) play a crucial role in the response syndrome and phenotypic plasticity and mediate the adaptation to fluctuating environments. Here, we performed the first genome-wide identification and characterization of the HSP70 family in a Neotropical terrestrial gastropod of high conservation concern: the Cuban painted snail Polymita picta. Using comprehensive bioinformatic approaches, we identified HSP70 paralogs, analysed their structural features and assessed sequence variation, highlighting their potential relevance for thermoresistance. Our findings reveal an HSP70 repertoire of ten diversified sequences with signatures of functional specialization and possible adaptive variation linked to environmental temperature regimes. Using novel molecular resources, this pioneering analysis establishes a baseline for early warning systems, integrating stress-related biomarkers into conservation management and climate change adaptation strategies for threatened terrestrial molluscs.

genomics↗

bioRxiv2022

Simulation-based assessment of the performance of hierarchical abundance estimators for camera trap surveys

The need for knowledge about abundance to guide conservation and management strategies in combination with low detectability of many species has led to a widespread use in ecology and management of a range of hierarchical models (HMs) for abundance. These models also appear like good candidates for inference about local abundance in nature reserves studied by camera traps. However, the best choice among these models is unclear, particularly how they perform in the face of several complicating features of realistic populations that include: (i) movements relative to sites, (ii) multiple detections of unmarked individuals within a single survey, and (iii) low probabilities of detection. We conducted a simulation-based comparison of three HMs (Royle-Nichols, binomial N-mixture and Poisson N-mixture model) in the context of small populations of elusive animals in a single study area, where animals cannot be distinguished individually and hence double counting occurs. We generated count data by simulating camera traps monitoring individuals moving according to a Gaussian random walk. Under the simulated scenarios none of the three HMs yielded accurate abundance estimates. Moreover, the performance of each HM depended on the interpretation of abundance. By pooling abundance estimates for trend estimation, each models performance markedly improves. Overall, the Royle-Nichols and Poisson N-mixture models outperform a binomial N-mixture model. This emphasizes the importance of choosing the appropriate HM for the data problem.

ecology↗

bioRxiv2021

Managing African Swine Fever: Assessing the Potential of Camera Traps in Monitoring Wild Boar Occupancy Trends in Infected and Noninfected Zones, Using Spatio-temporal Statistical Models

The recent spreading of African swine fever (ASF) over the Eurasian continent has been acknowledged as a serious economic threat for the pork industry. Consequently, an extensive body of research focuses on the epidemiology and control of ASF. Nevertheless, little information is available on the combined effect of ASF and ASF-related control measures on wild boar (Sus scrofa) population abundances. This is crucial information given the role of the remaining wild boar that act as an important reservoir of the disease. Given the high potential of camera traps as a non-invasive method for ungulate trend estimation, we assess the effectiveness of ASF control measures using a camera trap network. In this study, we focus on a major ASF outbreak in 2018-2020 in the South of Belgium. This outbreak elicited a strong management response, both in terms of fencing off a large infected zone as well as an intensive culling regime. We apply a Bayesian multi-season site-occupancy model to wild boar detection-nondetection data. Our results show that (1) occupancy rates at the onset of our monitoring period reflect the ASF infection status; (2) ASF-induced mortality and culling efforts jointly lead to decreased occupancy over time; and (3) the estimated mean total extinction rate ranges between 22.44% and 91.35%, depending on the ASF infection status. Together, these results confirm the effectiveness of ASF-control measures implemented in Wallonia (Belgium), which has regained its disease-free status in December 2020, as well as the usefulness of a camera trap network to monitor these effects.

ecology↗