Biology subjects

Arce-Valdes, L. R.

Publications and source records attributed to Arce-Valdes, L. R..

4 recordsLinked to original sources

bioRxiv2025

Hybridization outcomes reflect context-dependent reproductive isolation in two damselfly hybrid zones

Pair of species with multiple hybrid zones provide powerful systems to examine how reproductive isolation and reinforcement may depend on ecological and demographic contexts. We conducted a comparative analysis of two hybrid zones between Ischnura elegans and Ischnura graellsii in North-central (NC) and North-western (NW) Spain to evaluate how differences in reproductive barriers shape patterns of hybridization and admixture. First, we quantified five prezygotic barriers in the NC hybrid zone--where no barrier estimates previously existed--and compared them with published data from the NW hybrid zone. Second, we conducted genomic analyses using 5,702 SNPs to assess genetic structure, differentiation, and diversity between species; and 381 SNPs with species-specific alleles to characterize hybrid classes and introgression across both regions. Reproductive isolation was strongly context dependent. Mechanical reinforcement acted in the same cross direction in both hybrid zones, but the NC hybrid zone also showed stronger gametic (fertility) isolation. Consequently, total prezygotic isolation was higher in the NC hybrid zone. These differences were also observed genomically: the NC hybrid zone exhibited limited and largely unidirectional introgression, whereas the NW hybrid zone showed more extensive admixture, bidirectional gene flow, and reduced interspecific differentiation, consistent with a longer or more sustained history of hybridization. Our results demonstrate that hybridization outcomes can differ markedly between hybrid zones involving the same pair of species, underscoring the importance of evaluating spatial variation in reproductive barriers and introgression to assess the presence, asymmetry, and repeatability of reinforcement, as well as the microevolutionary processes shaping hybrid zone structure.

evolutionary biology↗

bioRxiv2025

Using insects for sustainable waste management of superabundant animals.

Management of fecal waste from superabundant wildlife in urban areas is a key environmental and public health concern, yet even in developed countries, sustainable solutions that implement circular economy principles are still lacking. We tested the potential of black soldier fly (BSF) larvae for valorizing organic waste of the widespread Canada goose: converting droppings into larval protein while yielding frass fertilizer. Larvae were able to survive, develop, and degrade the goose feces. For instance, larvae degraded 56% of goose feces compared to 63% of a control diet. Sterilization of feces reduced the performance of larvae. We tested the fertilization properties of the insect frass on an aquatic plant (duckweed) and we found growth enhancement of 32% at 10 g{middle dot}L-1 compared to a standard Hoaglands media. Our results provide insights into how to sustainably manage urban fecal waste from overabundant species while producing protein and a nutrient-rich fertilizer for plants.

ecology↗

bioRxiv2025

Alternative reproductive strategies explain asymmetric reinforcement of reproductive isolation in two Ischnura damselfly species

Theoretical and empirical studies on reinforcement have been a central focus in speciation research. Despite its significance, reinforcement in polymorphic species has received little attention, even though morphs often exhibit differences in behavior and reproductive capacity, which could drive asymmetric reinforcement. In this study, we tested for asymmetric reinforcement between morphs in the polymorphic damselflies Ischnura elegans and Ischnura graellsii, in which female morphs exhibit alternative reproductive strategies and males show a preference for the gynochrome morph. These species have formed two independent hybrid zones where reinforcement has strengthened a mechanical barrier and reproductive character displacement has shaped mating-related structures. We compared the strength of five reproductive barriers between female morphs to assess the interplay between female-limited color polymorphism and reinforcement. We detected asymmetric reinforcement in premating and postmating barriers between morphs in both hybrid zones, likely driven by their different reproductive strategies. Additionally, we observed weakening of oviposition and fertility barriers probably associated with gene flow and purging of incompatibilities. Our findings highlight that inherent asymmetry in reproductive isolation, caused by differences in female morph reproductive strategies, drive asymmetric reinforcement between morphs. Future studies should explore the cascading effects of this process and its implications for morph speciation.

evolutionary biology↗

bioRxiv2023

Testing the predictions of reinforcement: long-term empirical data from a damselfly mosaic hybrid zone

Theoretical work suggests that reinforcement can cause the strengthening of prezygotic isolation in sympatry by mitigating the costs of maladaptive hybridization. However, only a handful of studies have tested all predictions of this theory in natural populations. We investigated reinforcement in a mosaic hybrid zone of the damselflies Ischnura elegans and I. graellsii. Firstly, we tested if the conditions of reinforcement were fulfilled by quantifying whether hybridization was costly, and prezygotic isolation was strengthening in sympatry compared with in allopatry. Secondly, we investigated three specific predictions of reinforcement: rarer female effect, presence of concordant prezygotic and postzygotic isolation asymmetries in sympatry, and greater premating asymmetries associated with weaker postzygotic isolation in sympatry. We found that reinforcement has strengthened mechanical isolation in one cross direction between species in sympatry. Our study details a case of reinforcement and heterospecific gene flow causing opposite effects between reciprocal heterospecific crosses and describes a natural model in which reproductive isolation is built by the simultaneous effects of reinforcement, the lock-and-key model, Bateson-Dobzhansky-Muller incompatibilities and Haldanes rule.

evolutionary biology↗