Temperature during the free-living phase of an ectoparasite influences the emergence pattern of the infective phase

Abstract

SUMMARYUnderstanding the population dynamics and co-evolution of host-parasite systems requires detailed knowledge of their phenology what, in turns, requires a deep knowledge on the effect of abiotic factors on the life cycle of organisms. Temperature is known to be a key environmental influence that participates in the regulation of diapause. Yet, not much is known about the effect of temperature on the free-living stages of true parasites and the way it may influence host-parasite interactions. Here we experimentally study the effect of ambient temperature on overwintering pupae of Carnus hemapterus (Diptera, Carnidae), an ectoparasitic fly of various bird species. We also test whether chilling is a prerequisite for completion of diapause in this species. In the course of three winter seasons we experimentally exposed carnid pupae from nests of various host species to spring temperature with and without chilling and recorded the emergence pattern in experimental and control groups. Experimental groups showed an advanced emergence date, a lower emergence rate and, consequently, a protracted emergence period. Chilling had no obvious effect on the start of emergence but it did advance the mean emergence date, shortened the length of the emergence period when compared to the control treatment and increased the emergence rate when compared with the spring treatment. This study identifies an environmental cue, namely temperature during the free-living stage, affecting the emergence of a widespread parasite and evidences the plasticity of diapause in this parasite. Our findings are of potential significance in understanding host -parasite interactions.

Coexistence, habitat associations and puparia description of three dipteran species of the Family Carnidae

“…The determination of key traits for the identification of various stages of closely related species is important because it enables further studies on significant processes occurring at these phases (e.g. diapause during the pupal phase, see Amat-Valero et al 2013 for C. hemapterus ) that are frequently longer than the adult phase for many insect species. Moreover, the possibility of identifying sister taxa facilitates comparative studies on relevant topics such as coexistence, niche partitioning or the evolution of life histories (Tauber and Tauber, 1981, 1982).…”

Begging and ectoparasite attraction

“…This would be especially adaptive for nestdwelling ectoparasites of birds, which are known to pupate or enter diapause within the nest materials or in the immediate surroundings of bird nests (e.g. Amat-Valero, Calero-Torralbo, & Valera, 2013;Burtt, Chow, & Babbitt, 1991;Fessl et al, 2006;Harper, Marchant, & Boddington, 1992). Termination of diapause in insects has been traditionally considered to be triggered by abiotic factors such as temperature, humidity or photoperiod (Tauber, Tauber, & Masaki, 1986).…”

Dipteran assemblages in Red-footed Falcon (Falco vespertinus) nest boxes

“…In former investigations, only 8 dipteran species, C. hemapterus, Cynomya mortuorum, Meoneura neottiophila, Ornithomya avicularia, Potamia littoralis, Protocalliphora avium, Scenopinus fenestralis and Scoliocentra brachypterna were known to occur in the nests of the four bird species involved in our study (Red-footed Falcon, Common Kestrel, Jackdaw and Long-eared Owl) (Hicks 1959, Hicks 1962, Bohm 1978, Rotheray 2012, Amat-Valero et al 2013, Sumasgutner et al 2014, Lange 2015. We found only three of these species (C. hemapterus, M. neottiophila, S. fenestralis), therefore, all the other 39 species are new for the nest fauna of these birds.…”