Oviposition site selection and attachment ability of Propylea quatuordecimpunctata and Harmonia axyridis from the egg to the adult stage

Abstract

Surface features of plants can influence the searching efficiency and survival of predatory insects. Surfaces act as barriers preventing attachment of both phytophages and also their insect predators. In this regard, we focused on the oviposition site selection and the attachment ability of all life stages (eggs, larvae, imagines) of two common ladybird species, Propylea quatuordecimpunctata and Harmonia axyridis (Coleoptera: Coccinellidae), on artificial and natural substrates with different surface features and properties (roughness, wettability). Both species preferred a hydrophilic surface as the oviposition site and this can be correlated with the better performance of both larvae and adults on these substrates compared with hydrophobic ones. The egg glue of both ladybird species can wet hydrophobic surfaces such as those of many plant leaves and also with prominent 3D wax coverage. The surface roughness has an important role in the oviposition site selection in P. quatuordecimpunctata, but not in H. axyridis. The oviposition preference for smooth surfaces in P. quatuordecimpunctata could be due to better performance of larvae on smooth substrates compared with rough ones. The egg glue of both species can adapt to artificial and natural surfaces characterized by different asperity sizes faithfully replicating their shape, except for very high asperity sizes or big trichomes. The results of the present research can shed light on the mechanical ecology of the evolutionary successful Coccinellidae and may aid in the development of suitable substrates for coccinellid egg-laying, in order to improve the mass rearing technique of species used in biological control.

Effects of aphid‐induced semiochemicals from cover plants on Harmonia axyridis (Coleoptera: Coccinellidae)

“…Another study also showed that surface roughness had little effect on the oviposition site selection of H. axyridis, although it is known to be an important factor for Propylea quatuordecimpunctata L. (Coleoptera: Coccinellidae). 31 H. axyridis females did show an ovipositional preference for the lower surface of leaves, regardless of the plant species. Coccinellids have shown different degrees of negative geotropism in egg-laying behavior, 32 including H. axyridis.…”

“…These results suggest that all four cover plants were suitable for H. axyridis oviposition, therefore it can be inferred that different surface features had little or no influence on the oviposition of H. axyridis . Another study also showed that surface roughness had little effect on the oviposition site selection of H. axyridis , although it is known to be an important factor for Propylea quatuordecimpunctata L. (Coleoptera: Coccinellidae) 31 . H. axyridis females did show an ovipositional preference for the lower surface of leaves, regardless of the plant species.…”

“…H. axyridis females did show an ovipositional preference for the lower surface of leaves, regardless of the plant species. Coccinellids have shown different degrees of negative geotropism in egg‐laying behavior, 32 including H. axyridis 31 . The great attachment ability of H. axyridis adults allows females to walk upside down and oviposit on the lower surface of leaves, 31 where eggs are protected from predators and abiotic factors.…”

“…Coccinellids have shown different degrees of negative geotropism in egg‐laying behavior, 32 including H. axyridis 31 . The great attachment ability of H. axyridis adults allows females to walk upside down and oviposit on the lower surface of leaves, 31 where eggs are protected from predators and abiotic factors. The optimal oviposition theory suggests that insects should oviposit on positions that can benefit their progeny most.…”

Mechanical interaction of the egg parasitoid Anastatus bifasciatus (Hymenoptera: Eupelmidae) with artificial substrates and its host egg

“…The roughness of different polishing paper with asperity sizes of 0.3, 1, 3, 9, 12, 35 and 125 μm was characterized using the white light interferometer (Salerno et al, 2017). Roughness data are reported in Salerno et al (2022).…”