Role of long-chain hydrocarbons in the aggregation behaviour of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)

in Journal of Insect Physiology (2012)

The multicoloured Asian ladybeetles, Harmonia axyridis (Pallas), form large aggregations inside dwellings to survive cold winters, causing annoyances to householders from their number and sometimes the ... [more ▼]

The multicoloured Asian ladybeetles, Harmonia axyridis (Pallas), form large aggregations inside dwellings to survive cold winters, causing annoyances to householders from their number and sometimes the induction of allergic reactions. Migratory flight and macrosite choice of this species is well documented. H. axyridis shows a hypsotactic behaviour and a clear preference for contrasting visual elements. However, how the microsite is selected remains undocumented, although a better understanding of the implicated factors could lead to the development of new control methods for this pest. In this work, we have hypothesized that non-volatile compounds are involved in the microsite choice and the aggregation process of this beetle. Long chain hydrocarbons were identified inside aggregation sites, comprising saturated and unsaturated homologues. An aggregation bioassay was then conducted on overwintering individuals, highlighting the retention capacity of the previously cited compounds on the tested ladybeetles. Additional investigations have shown that H. axyridis males and females, originating from overwintering sites, deposit a similar blend of molecules while walking. A Y-shaped tube assay revealed that this blend is used by male and female congeners as cue, allowing individuals to orientate towards the treated side of the olfactometer. These results suggest the use of two different blends of long chain hydrocarbons by H. axyridis during its aggregative period, the first one to lead conspecifics towards aggregation sites (microsites) and the second to ensure the cohesion of the aggregation. These findings support the potential use of these blends, in association with volatiles, in the design of traps in order to control infestations of this species in dwellings. [less ▲]

The chemical ecology of Harmonia axyridis

in Roy, Helen; Ware, Remy; Handley-Lawson, Lori (Eds.) et al Invasive arthropod predators and parasitoids: an ecological approach (2011)

We review the chemical ecology of the ladybird beetle Harmonia axyridis from the perspective of its invasiveness and the deleterious effects it exerts in the regions it has colonised. We outline the ... [more ▼]

We review the chemical ecology of the ladybird beetle Harmonia axyridis from the perspective of its invasiveness and the deleterious effects it exerts in the regions it has colonised. We outline the nature and quantification of its chemical defence, and discuss the protection this provides from natural enemies, particularly intraguild predators. We consider the role played by infochemicals in location of prey, intraspecific communication and intraguild interactions; we also discuss the role of prey allelochemicals in relation to H. axyridis extreme dietary generalism. Harmonia axyridis poses a number of practical problems for human health and well-being, including “lady beetle taint” wine contamination and problems consequent on large aggregations overwintering in buildings. We discuss chemical insights into these issues and, in particular, how attractants and repellents might help manage H. axyridis populations. We conclude by discussing future perspectives for research. [less ▲]