Reproduction and Offspring Sex Ratios Differ Markedly among Closely Related Hyperparasitoids Living in the Same Microhabitats

Abstract

Closely related species in nature usually exhibit very similar phylogenetically conserved traits, such as reproduction, behavior and development. Here, we compared fecundity schedules, lifetime reproductive success and offspring sex ratios in three congeneric facultative hyperparasitoid wasps that exhibit several overlapping traits and which co-occur in the same small-scale habitats. Gelis agilis, G. proximus and G. hortensis are abundant in meadows and forest edge habitats in the Netherlands. Gelis agilis is asexual (all female), whereas the other two species reproduce sexually. Here they developed on cocoons of the primary parasitoid Cotesia glomerata. When provided with unlimited hosts, lifetime reproductive success was three times higher in G. proximus than in G. agilis with G. hortensis producing intermediate numbers of offspring. All three species depleted their teneral reserves during their lives. Females of G. proximus and G. hortensis lived significantly longer than females of G. agilis. Offspring sex ratios in young G. proximus mothers were female-biased and marginally malebiased in G. hortensis. As mothers aged, however, the ratio of male:female progeny produced rapidly increased until no daughters emerged later in life. Our results reveal significant differences in reproductive traits among the three species despite them cooccurring in the same microhabitats, being very closely related and morphologically similar. The increase in the production of male progeny by Gelis mothers over time suggests a depletion in sperm number or viability with age. This is especially interesting, given that Gelis species are among the least fecund parasitoids thus far studied. It is likely that in the field most Gelis mothers are probably only able to parasitize a few hosts and to maintain the production of female offspring.

The remarkable biology of a new species of Gelis Thunberg, 1827 (Ichneumonidae, Phygadeuontinae), a solitary endoparasitoid of fresh eggs of Timarcha (Coleoptera, Chrysomelidae)

“…Although no doubt temperature-dependent this would probably amount to no more than an average of around four ovipositions per female per day (cf. Muesebeck and Dohanian 1927;Harvey et al 2019). Thus there were a few instances in which a functional-age and well-fed female G. timarchae failed to oviposit into a 2-day old host egg under experimental circumstances that otherwise seemed suitable and, because we also found small egg batches in the wild from which both Timarcha larvae and G. timarchae emerged, this clearly happens in the field as well.…”

“…obs. ), and can also be deduced from field data in several of the relatively unspecialised species of Gelis when they encounter aggregated resources such as cocoon batches of gregarious microgastrine braconids (Schwarz and Shaw 1999; see also Harvey 2008;Harvey et al 2019).…”

Divergencia en la estrategia reproductiva de dos especies simpátricas de <i>Anthurium</i> (Araceae) en un bosque andino tropical

“…Otros factores, como la menor temperatura a mayor elevación podrían afectar la producción de semillas (Bergman et al 1996). Además, se ha reportado mayor propagación clonal en poblaciones Este estudio provee evidencia de como dos especies con estrecha relación filogenética del género Anthurium exhiben diferentes estrategias reproductivas y responden de manera diferente a un intervalo ambiental (i.e., elevación), de manera que la divergencia en patrones de inversión de recursos entre especies facilita su coexistencia a pequeña escala (Sedio et al 2012, Harvey et al 2019. Esto, acoplado al aislamiento reproductivo fenológico restringe el flujo génico entre especies (i.e.…”

“…Especies cercanamente relacionadas usualmente exhiben caracteres similares que son conservados filogenéticamente, tales como la morfología, fisiología, reproducción, comportamiento y desarrollo, lo cual resulta en requerimientos ambientales similares (Zhou et al 2016). Como consecuencia, puede ocurrir competencia interespecífica intensa entre ellas, especialmente cuando ocupan el mismo hábitat (Harvey et al 2019).…”

“…esfuerzo reproductivo) debe experimentar una reducción en la producción de frutos o en reproducción futura (i.e. costo de la reproducción), debido a que los recursos destinados para reproducción no son ilimitados (Bazzaz et al 2000, Harvey et al 2019. De esta manera, una producción alta de semillas ocurre a expensas de la sobrevivencia, el crecimiento o la reproducción futura de la planta (Begon et al 2006).…”