Effects of food plant and group size on predator defence: differences between two co‐occurring aposematic Lygaeinae bugs

Abstract

Summary 1. The role of food plant and aggregation on the defensive properties of two aposematic sympatrically occurring seed bugs, Tropidothorax leucopterus and Lygaeus equestris (Lygaeinae, Heteroptera), was investigated. Larvae reared on seeds either of their natural host plant Vincetoxicum hirundinaria (Asclepiadaceae) or of sunflower Helianthus annuus were subjected to predation by chicks. 2. The two species differ in their dependency on the host for their defence. Lygaeus equestris was better defended on its natural host plant than on the alternative food, as indicated by fewer attacks, lower mortality, and predator avoidance after experience. No such effect of food plant could be found for T. leucopterus, suggesting the existence of alternative defences in this species. 3. The number of attacks was lower when host plant‐fed larvae of both species were presented in groups. 4. The discussion concerns how major components of an aposematic syndrome, such as host plant chemistry, insect colouration, and aggregation, are integrated with other life‐history traits to form alternative lifestyles in L. equestris and T. leucopterus.

Predator dependent mimetic complexes: Do passerine birds avoid Central European red-and-black Heteroptera?

“…By careful handling the aposematic prey, robins may detect less defended individuals (automimics) in those insect species, where the degree of unpalatability varies owing to sequestration of defensive chemicals from various hostplants. There is a possibility of automimicry in L. equestris (Tullberg et al, 2000) and S. saxatilis (P. Ba a , unpubl. data).…”

“…It is generally understood that red-and-black Heteroptera form mimetic complexes (see Schuh & Slater, 1995), although their nature, extent, model-mimic relationships and in some cases their very existence are often suspect and mostly lack experimental evidence. Only few comparative studies on several different live aposematic heteropteran species tested with same predators were carried out (Schlee, 1986;Evans et al, 1987;Gamberale-Stille & Tullberg, 1999;Tullberg et al, 2000). Exnerová et al (2003aExnerová et al ( , 2007 showed differences among bird predators in reactions to aposematic prey; consequently, we can assume that also mimetic complexes could be predator dependent.…”

The Biology of Invasive Alien Plants in Canada. 2. Cynanchum rossicum (Kleopow) Borhidi [= Vincetoxicum rossicum (Kleopow) Barbar.] and Cynanchum louiseae (L.) Kartesz & Gandhi [= Vincetoxicum nigrum (L.) Moench]

“…The lygus bugs, Lygaeus equestris (L.) and Tropidothorax leucopterus Goeze (Lygaeinae), are reported to feed on seeds of C. vincetoxicum (Kugelberg 1973;Solbreck et al 1989;Tullberg et al 2000). The effect of Lygaeus equestris on seed production is relatively minimal, given that this insect is primarily a post-dispersal seed predator (Solbreck and Sillén-Tullberg 1986).…”

Maternal effects and the evolution of aposematic signals

“…In turn, coloration and morphology in many insects are dramatically influenced by early larval environment, including polymorphisms of cryptic and aposematic forms in the geometrid moth Nemoria (23) and desert locusts of the genus Schistocerca (22,35). Differences in larval diet are known to alter the redness of some lygaeid bugs (36) and ladybird beetles (37). Both juvenile and adult diets alter palatability through sequestration of plant compounds as observed in arctiid moths, Utetheisa (25,26), and may similarly alter olfactory warning signals (24).…”