First insights into the chemical defensive system of the erotylid beetle, Tritoma bipustulata

Life History of Erotylina jaspidea (Erichson, 1847) (Coleoptera, Erotyloidea, Erotylidae, Erotylini)

The life history of Erotylina jaspidea (Erichson, 1847) (Coleoptera, Erotyloidea, Erotylidae, Erotylini) is described. A female specimen was found in an Atlantic Forest remnant in Northeast Brazil. After oviposition, individuals were reared in Petri dish and terrarium, feeding on basidiomes of Lentinus substrictus (Bolton) Zmitr. & Kovalenko, Favolus tenuiculus P. Beauv (Polyporaceae) and an unidentified resupinate fungus. Growth and feeding behaviors were regularly observed. We provide information on the observed life history stages, together with morphological descriptions, and photographs of eggs, larvae, pupae and adults. We compared our description of the teneral E. jaspidea to species of similar color pattern. Furthermore, we discuss hypotheses about larval defensive behavior and total instar durations in E. jaspidea and other Erotylinae representatives. The present work is the first to provide a description for the life history of a species of the genus Erotylina.  

The scent chemistry of butterflies

Butterflies use structurally highly diverse volatile compounds for communication, in addition to visual signals. These compounds originate from plants or a formed de novo especially by male butterflies that possess specific scent organs.

First observation on the predation of a non-arthropod species by a dung beetle species: The case of Canthon chalybaeus and the snail Bulimulus apodemetes

We described, for the first time, a case of predation of a non-arthropod species by a dung beetle species. Canthon chalybaeus Blanchard, 1843 kills healthy individuals of the terrestrial snail Bulimulus apodemetes (D'Orbigny, 1835) showing an evident pattern of physical aggressiveness in the attacks using the dentate clypeus and the anterior tibiae. The description of this predatory behaviour was complemented with the analysis of the chemical secretions of the pygidial glands of C. chalybaeus, highlighting those main chemical compounds that, due to their potential toxicity, could contribute to death of the snail. We observed a high frequency of predatory interactions reinforcing the idea that predation in dung beetles is not accidental and although it is opportunistic it involves a series of behavioural sophistications that suggest an evolutionary pattern within Deltochilini that should not only be better studied from a behavioural point of view but also phylogenetically.

Physiological costs of chemical defence: repeated reflex bleeding weakens the immune system and postpones reproduction in a ladybird beetle

In insects, external chemical defences, such as reflex bleeding, have been proved to be an efficient strategy against various predators. At the same time, significant costs of reflex bleeding can be expected because bled haemolymph is lost and all valuable components included have to be renewed. Interestingly, this issue has rarely been investigated for adult insects. In this study, we examined the immune and fitness costs of repeated reflex bleeding in adults of the invasive ladybird Harmonia axyridis, investigating several haemolymph parameters. Reflex bleeding induced twice a week for three weeks resulted in a significant reduction in haemocyte concentration, total protein content, and antimicrobial activity against Micrococcus luteus, and a marginally non-significant decrease in antimicrobial activity against Escherichia coli. Repeated reflex bleeding did not result in significant body mass reduction. Interestingly, resource limitation in the form of complete food absence did not significantly interact with reflex bleeding, even though starvation itself had a strong negative effect on all haemolymph parameters investigated and individual body mass. Daily reflex bleeding did not result in decreased fecundity of young ladybirds during the first 30 days of their adult life, but the start of ladybird reproduction was delayed by about two days. Moreover, ladybirds bleeding larger amounts of haemolymph started their reproduction significantly later. Overall, our results indicate that repeated reflex bleeding weakens a ladybird’s immune system and can increase their susceptibility to pathogens, but a ladybird’s reproductive potential remains almost unaffected, even by very intensive reflex bleeding.