Changes in life history traits and transcriptional regulation of Coccinellini ladybirds in using alternative prey

Abstract

Background: Ladybird beetles (Coleoptera, Coccinellidae) are highly diverse in their feeding habits. Most of them are specialist feeders, while some can have a broad spectrum of prey. As a representative group of generalists, the tribe Coccinellini includes many aphidophagous species, but members of this tribe also feed on other hemipterous insects including coccids, psyllids and whiteflies. As a result, several species are effective biological control agents or invasive species with serious non-target effects. Despite their economic importance, relatively little is known about how they adapt to new prey. Results: In this study, comparisons of the life history traits and transcriptomes of ladybirds fed initial (aphids) and alternative prey (mealybugs) were performed in three Coccinellini species. The use of alternative prey greatly decreased performance, implied by the significantly prolonged development time and decreased survival rate and adult weight. Prey shifts resulted in a set of differentially expressed genes encoding chemosensory proteins and digestive and detoxifying enzymes. Conclusions: Our results suggest that these generalists do not perform well when they use alternative prey as the sole nutrition source. Although their capacity for predation might have created an opportunity to use varied prey, they must adapt to physiological obstacles including chemosensing, digestion and detoxification in response to a prey shift. These findings challenge the effect of Coccinellini predators on the biological control of non-aphid pests and suggest the possibility of non-target attacks by so-called specialists.

Genomic insight into the scale specialization of the biological control agent Novius pumilus (Weise, 1892)

“…Among these species, four are ladybird species of the Coccinellidae family ( Coccinella septempunctata , Propylea japonica , Harmonia axyridis and Cryptolaemus montrouzieri ) with available genome sequences, and they exhibit apparently a relatively wider prey range than N. pumilus . These four ladybirds can feed on aphids, mealybugs and whiteflies [ 1 ], while N. pumilus mainly feeds on the pests of the Icerya [ 103 ]. There have been several genomes of H. axyridis sequenced, among which we only selected a chromosome-level genome from Chen et al (2021) [ 33 ] to use in the analysis.…”

“…Ladybirds (Coleoptera, Coccinellidae) are a group with diverse feeding habits. Most of them are specialist feeders, while some species have a much wider range of prey [ 1 ]. Evolutionary studies have suggested that the ancestors of modern ladybirds switched from mycophagy to scale insects feeding, and some species have even shifted the feeding behaviors to plants, mites, whiteflies and aphids [ 2 , 3 ].…”

Entomofauna asociada a tres especies arvenses del género Cleome Linnaeus, 1753 (Brassicales: Cleomaceae) y sus relaciones potenciales con cultivos agrícolas

“…Este coccinélido es una de las especies dominantes en ensamblajes de depredadores asociados a plantas no cultivadas que crecen naturalmente en el agroecosistema. De acuerdo con Chen et al (2020), es una especie generalista que se alimenta de áfidos, ácaros, escamas y moscas blancas, pero también puede nutrirse de alimentos que no son presas.…”

Depredación, reproducción y desarrollo de la catarina Hippodamia convergens (Coleoptera: Coccinellidae)

“…y a plantas no cultivadas que crecen naturalmente en este agroecosistema en el suroccidente colombiano (Melo-Cerón & Manzano, 2017). Hippodamia convergens es una especie generalista que se alimenta de áfidos, ácaros, escamas y moscas blancas (Chen et al, 2020) pero también puede nutrirse de alimentos que no son presas (Lundgren, 2009). Debido a que el depredador se hospeda en plantas no cultivadas, en presencia o ausencia de los áfidos, y que U. nigrotibium es un áfido grande (0.5-0.8 mm en promedio), vistoso y expuesto a la depredación, mientras que R. maidis es un áfido pequeño (0.1-0.3 mm) que se encuentra oculto dentro de la panícula de maíz, o expuesto en la inflorescencia, nuestra primera hipótesis es que H. convergens presenta una tasa de depredación en estado de larva más alta sobre U. nigrotibium y esto favorecería el desarrollo del coccinélido.…”