Repeated probing of hosts: an important component of superparasitism

Abstract

Parasitoids that encounter a previously parasitized host inspect it externally and internally, sometimes eventually laying additional eggs (superparasitism). The fitness effects of increased clutch sizes generated through superparasitism are widely studied, whereas the consequences of multiple host probings during the inspection received less attention. To address this issue, we offered a host to 1-5 females of the encyrtid wasp Copidosoma koehleri consecutively, or presented it 1-5 times to a single female. We noted whether the hosts died before pupation of either host or wasp, produced parasitoid pupae, or developed into moth pupae. Additional hosts were dissected after varying numbers of probings to determine their parasitoid egg loads. Host rejection rates prior to ovipositor insertion did not differ between treatments. Host rejections after ovipositor insertion, characterized by brief (<10 s) probing durations, were more common in the single-than in the multiple-female treatment. This could reflect avoidance of self-superparasitism, or increased selectivity by host-experienced females. Egg number per host increased with the number of prolonged probings in both treatments. Some hosts that received 1-2 probings (brief or prolonged) yielded moth pupae, while no hosts with five probings survived to pupation. Hosts probed three times (corresponding to <1 and 2.2 eggs in the single-and multiple-female treatments, respectively) produced the largest proportion of parasitoid pupae. The parasitoids' success is thus strongly affected by the number of host probings. Overcoming host defenses through repeated probings is a previously overlooked potential benefit of superparasitism.

Impacts of differences in nutritional quality of wingless and winged aphids on parasitoid fitness

“…It might be that winged individuals develop a lower physiological defence and that this is a counterpart of flight and associated costs (Parker et al, 2017). Alternatively, wingless instars might be more superparasitized than winged instars as they suffer from a higher mortality rate (Bai and Mackauer, 1992;Keinan et al, 2012). We did not strictly control for superparasitism as in Khatri et al (2017).…”

Tendency and consequences of superparasitism for the parasitoid Ooencyrtus pityocampae (Hymenoptera: Encyrtidae) in parasitizing a new laboratory host, Philosamia ricini (Lepidoptera: Saturniidae)

“…Similarly, a study on Metaphycus fl avus (Hymenoptera: Encyrtidae) has demonstrated that laying several eggs in a single host suppresses the host's immune defences and reduces egg encapsulation (Kapranas et al, 2012). This would make self-superparasitism advantageous (Puttler, 1959(Puttler, , 1967Streams, 1971;Blamberg & Luck, 1990;Quicke, 1997;Montoya et al, 2000;Keinan et al, 2012).…”

Sex Allocation in a Polyembryonic Parasitoid with Female Soldiers: An Evolutionary Simulation and an Experimental Test

“…C. koehleri is a koinobiont egg-larval parasitoid of the potato tuber moth, Phthorimaea operculella (Gelechiidae: Lepidoptera). One egg is generally laid per ovipositor insertion into a host egg, but hosts often receive an additional egg during a later oviposition, thus becoming super-parasitized [12]. Eggs that develop within super-parasitized hosts may be of one sex or of different sexes.…”

“…Female clones contain a morphologically distinct soldier larva that develops precociously, attacks competitors and dies before emerging from the host [15]. A high proportion of hosts contain two or more clones [16], which are usually mothered by different females [12], [17]. In hosts that contain both a male and a female clone, the female soldier eliminates some of the males, reducing the proportion of emerging males in the brood [16].…”