Behavioural and physiological responses to prey-related cues reflect higher competitiveness of invasive vs. native ladybirds

Abstract

Understanding the traits that might be linked with biological invasions represents a great challenge for preventing non-target effects on local biodiversity. In predatory insects, the ability to exploit habitats for oviposition and the physiological response to prey availability differs between species. Those species that respond more readily to environmental changes may confer to their offspring a competitive advantage over other species. Here, we tested the hypothesis that the invasive Harmonia axyridis (Coleoptera: Coccinellidae) makes better use of information from a plant-prey (Vicia faba - Aphis fabae) system compared to the native Oenopia conglobata. Y-tube olfactometer bioassays revealed that both species used olfactory cues from the system, but H. axyridis exhibited a more complete response. This species was also attracted by plants previously infested by aphids, indicating the capacity to exploit volatile synomones induced in plants by aphid attack. Oocyte resorption was investigated when different olfactory stimuli were provided under prey shortage and the readiness of new oogenesis was measured when prey was available again. H. axyridis exhibited higher plasticity in oogenesis related to the presence/absence of plant-aphid volatiles. Our results support the hypothesis that H. axyridis is more reactive than O. conglobata to olfactory cues from the plant-prey system.

Antennal sensory organs and glands of the harlequin ladybird, Harmonia axyridis

“…When moving through the landscape, the ladybird female presumably explores reliable cues from suitable plant‐prey systems, as well as cues from other predatory insects (Obata, 1986; Agarwala et al, 2003; Alhmedi et al, 2010; Almohamad et al, 2010; Sloggett et al, 2011; Leroy et al, 2012a,b; Rondoni et al, 2017). Some of these signals are released over a longer distance, whereas others are deposited only on the patch.…”

Antennal Transcriptome Analysis and Identification of Candidate Chemosensory Genes of the Harlequin Ladybird Beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)

“…Behavioural and electrophysiological experiments demonstrated that H. axyridis responds to volatile semiochemicals [ 1 , 31 , 32 ]. Additionally, various types of antennal chemoreceptor sensilla (notably basiconica, chaetica, and grooved peg) have been recently characterized [ 33 ].…”

Molecular detection of field predation among larvae of two ladybird beetles is partially predicted from laboratory experiments

“…Because ladybird beetles have to deal with aphid colonies, which increase quickly but also quickly disappear from the agroecosystems, these predators are often forced to look for alternative preys to sustain their development 36 . In this scenario, some ladybird species might exhibit complex and unpredictable responses that confer them a competitive advantage over similar predators 37 . IGP, in particular, can foster the abundance of one ladybird species upon other predators 11 .…”