Parasite infestation influences life history but not boldness behavior in placental live-bearing fish

Abstract

Parasites can negatively affect the reproductive success of hosts. Placental species may be particularly susceptible, because parasite-induced stress during pregnancy could potentially influence embryo development. Here, we examine the consequences of a trematode infestation (black spot disease, BSD) for fetal development and adult behavior in 19 natural populations of the placental live-bearing fish species Poeciliopsis retropinna (Poeciliidae) in Costa Rica. First, we observed substantial variation in parasite infestation among populations which correlated with a number of local environmental conditions (elevation, river width, depth, and flow velocity). Furthermore, we observed substantial variation in parasite infestation among females within populations associated with maternal age and size. We found that the infestation rate significantly influenced embryonic development, with more heavily parasitized females producing smaller and worse-conditioned offspring at birth, possibly, because a costly immune response during pregnancy limits, either directly or indirectly, nourishment to developing embryos. Finally, a behavioral experiment in the field showed that the infestation rate did not affect an individual’s boldness. Our study indicates that in placental live-bearing fish parasite infestation leads to reduced embryo provisioning during pregnancy, resulting in a smaller offspring size and quality at birth potentially with negative implications for offspring fitness.

Multiple paternity in superfetatious live‐bearing fishes

“…turrubarensis (Zúñiga‐Vega et al, 2007) and P . retropinna (Hagmayer, Furness & Pollux, 2020; Hagmayer, Furness, Reznick et al, 2020).…”

Sex-dependent effects of infection on guppy reproductive fitness and offspring parasite resistance

“…Infected parents may change the quantity and quality of the offspring they produce, both because of the energetic constraints [1] or pathology [2–4] associated with infection, and because the optimal investment in defence [5–9] and reproductive strategy may differ under the threat of infection [10,11]. Intuitively, parental infection may induce the production of fewer, lower quality offspring due to decreased parental resources [12,13]. However, infection may also induce the production of more offspring as infected parents ‘terminally invest’: in the face of probable death, hosts increase reproductive output at the expense of their own defence against the infection [14].…”

“…Keywords: Gyrodactylus, heritable parasite resistance, life history, parental investment theory, parent-offspring regression, transgenerational immune priming, sex-specific response to infection Introduction: Infected parents may change the quantity and quality of the offspring they produce, both because of the energetic constraints (Tizard, 2008) or pathology (Armour et al, 2020;Billi et al, 2019;Khan et al, 2017) associated with infection, and because the optimal investment in defence (Boots & Bowers, 2004;Graham, 2013;Houston et al, 2007;Tschirren & Richner, 2006;Viney et al, 2005) and reproductive strategy may differ under the threat of infection (Schmid-Hempel, 2003;Sheldon & Verhulst, 1996). Intuitively, parental infection could induce the production of fewer, lower quality offspring due to decreased parental resources (Hagmayer et al, 2020;Vantaux et al, 2014). However, infection can also induce the production of more offspring as infected parents 'terminally invest': hosts increase reproductive output at the expense of their own defence against infection in an effort to produce offspring before their own death (Duffield et al, 2017).…”