Biology subjects

van der Kooi, C. J.

Publications and source records attributed to van der Kooi, C. J..

4 recordsLinked to original sources

bioRxiv2026

The diel structure and robustness of plant-pollinator networks are driven by the shifting influences of plant traits

O_LISpecies interactions are increasingly recognised as temporally dynamic. For plant-pollinator networks, evidence shows that interactions vary not only seasonally but also over the diel cycle. However, we still know little about what determines their diel structure, whether this structure is important for robustness to species loss, and which plant traits are associated with the roles plants play in this structure. These gaps are fundamental, because knowing what shapes networks over the diel cycle is required to predict the effects of global change drivers, such as light pollution, that may shift the timing of interactions. C_LIO_LIUsing 22 plant-pollinator networks sampled over morning, afternoon, and night, we addressed these gaps by applying a multilayer framework to characterise their diel structure, link it to robustness, and test which plant traits are associated with plant roles across diel periods (participation, versatility) and within them (centrality). C_LIO_LIDiel structure was non-random: interactions were segregated among diel periods yet integrated through plants visited across the diel cycle. Networks were more robust to simulated species loss when interactions were on average more evenly distributed across periods and when plants were more strongly interconnected among periods, although this benefit diminished when both properties were high simultaneously. The association between plant traits and their roles shifted with the temporal scale. Across diel periods, structural traits were the stronger predictors: taller plants were visited more evenly across the diel cycle (higher participation), whereas shorter plants shared pollinators with plants from multiple periods (higher versatility), potentially mediating indirect effects among them. Within diel periods, floral visual cues became more influential, with achromatic contrast the most consistent predictor: at night, plants with brighter flowers were well visited within the period, sharing pollinators with other plants of that period (higher centrality). C_LIO_LIThese findings identify diel structure as a functional axis of network organisation and indicate that plant-pollinator networks are assembled hierarchically: structural traits set a baseline across the diel cycle, whereas light conditions determine which traits matter within periods, ultimately defining distinct temporal pathways vulnerable to global change. C_LI

ecology↗

bioRxiv2026

Differential effectiveness of bee and beetle pollinators creates flower colour polymorphism

Floral diversity is the hallmark of Angiosperms and is often shaped by pollinator-mediated selection, which drives floral divergence as plants evolve traits that attract specific pollinator groups. Mediterranean red, bowl-shaped flowers are specialized on pollination by glaphyrid beetles in areas with beetles and bees but evolved different colours and specialize on bees as pollinators when beetles are absent. What explains this geographic variation in specialization and concomitant flower colour differences? We assessed pollination effectiveness of honeybees and glaphyrids for the colour-polymorphic Anemone pavonina in its natural habitat. We recorded the duration and number of flower visits and quantified single-visit seed set. Per-visit effectiveness (relative seed set) was threefold higher for Pygopleurus (36.3%) than for honeybees (9.5%). Flower visitation lasted substantially longer for beetles (56.3 sec. on average) than for honeybees (2.3 sec.). For beetles, pollinator importance (single-visit seed set x visitation frequency) was highest at low elevations but declined with increasing elevation, whereas for bees pollinator importance remained low yet constant across the elevational gradient. The high pollinator effectiveness of beetles indicates that floral specialization for this pollinator group is advantageous, even to the point that excluding low-quality bee pollinators - by producing inconspicuous flower colours - is beneficial. Non-red flowers may only be beneficial at higher elevations, where bee pollinator importance exceeds that of beetles.

animal behavior and cognition↗

bioRxiv2023

Ecological specialization and local adaptation in sympatric sexual and asexual grass thrips species

The maintenance of sex is difficult to explain in the face of the demographic advantages of asexuality, especially when sexual and asexual lineages co-occur and compete. Here, we test if niche divergence and specialization can contribute to the maintenance of sympatric populations of two closely related, sexual and asexual Aptinothrips grass thrips species. In mesocosm experiments, ecological niches and ecological specialization were inferred from thrips performances on different grass species used as hosts in natural populations. Sexual and asexual thrips performed best on different grass hosts, indicating niche differentiation. The asexual species was also characterized by a broader fundamental ecological niche than the sexual one. However, niche differentiation is unlikely to explain the maintenance of the two species in sympatry because the reproductive rate of asexual females generally exceeded that of sexual ones. Surprisingly, the asexual but not sexual species showed geographic variation in the fundamental niche. This geographic variation likely stems from different clonal assemblages at different locations because different asexual genotypes have different ecological niches. Across natural populations, the performance of asexual females on a specific grass species was further positively correlated with the frequency of that grass species, consistent with adaptation to locally abundant grasses. Altogether, our results suggest that niche differentiation contributes little to the maintenance of grass thrips species with different reproductive modes and that asexuality facilitates adaptation to a diversity of co-occurring host plants.

evolutionary biology↗

bioRxiv2019

Mapping of multiple complementary sex determination loci in a parasitoid wasp

Sex determination has evolved in a variety of ways and can depend on environmental and genetic signals. A widespread form of genetic sex determination is haplodiploidy, where unfertilized, haploid eggs develop into males and fertilized diploid eggs into females. One of the molecular mechanisms underlying haplodiploidy in Hymenoptera, a large insect order comprising ants, bees and wasps, is known as complementary sex determination (CSD). In species with CSD, heterozygosity at one or several loci induces female development. Here, we identify the genomic regions putatively underlying multi-locus CSD in the parasitoid wasp Lysiphlebus fabarum using restriction-site associated DNA sequencing. By analysing segregation patterns at polymorphic sites among 331 diploid males and females, we identify four CSD candidate regions, all on different chromosomes. None of the candidate regions feature evidence for homology with the csd gene from the honeybee, the only species in which CSD has been characterized, suggesting that CSD in L. fabarum is regulated via a novel molecular mechanism. Moreover, no homology is shared between the candidate loci, in contrast to the idea that multi-locus CSD should emerge from duplications of an ancestral single-locus system. Taken together, our results suggest that the molecular mechanisms underlying CSD in Hymenoptera are not conserved between species, raising the question as to whether CSD may have evolved multiple times independently in the group.\n\nAuthor summaryThe genetic or environmental signals that govern whether an organism develops into a male or female differ across species, and understanding their evolution is a key aspect of biology. In this paper, we focus on complementary sex determination (CSD), a genetic sex determination system found in many species of bees, ants and wasps where heterozygosity at one or multiple genetic regions determines the sex of the individual. We identify multiple genetic regions in the parasitoid wasp species Lysiphlebus fabarum that are likely underlying CSD. We show that these candidate CSD regions share no similarity with each other and that they differ from the CSD region known in the honey bee, the only species with a well-characterized CSD system. Our results suggest a different molecular mechanism underlying CSD in the wasp and that multiple CSD regions do not necessarily arise from duplications as generally thought.

genomics↗