0000000000767553
AUTHOR
Enric Frago
Winter feeding leads to a shifted phenology in the browntail moth Euproctis chrysorrhoea on the evergreen strawberry tree Arbutus unedo
1 The browntail moth Euproctis chrysorrhoea is a highly polyphagous univoltine forest pest. Although its young larvae usually overwinter in diapause from early autumn to the beginning of spring, winter larval feeding has been reported when this species feeds on the evergreen woody shrub strawberry tree Arbutus unedo. 2 The present study investigated life-history traits of four populations of E. chrysorrhoea feeding on A. unedo, including phenology of the different life stages, larval feeding activity and diapause incidence. By modelling the relationship between larval size and host plant leaf persistence, elevation and mean annual temperature, we also studied larval development in ten popul…
Bacterial symbionts in Lepidoptera: Their diversity, transmission, and impact on the host
The insect's microbiota is well acknowledged as a “hidden” player influencing essential insect traits. The gut microbiome of butterflies and moths (Lepidoptera) has been shown to be highly variable between and within species, resulting in a controversy on the functional relevance of gut microbes in this insect order. Here, we aim to (i) review current knowledge on the composition of gut microbial communities across Lepidoptera and (ii) elucidate the drivers of the variability in the lepidopteran gut microbiome and provide an overview on (iii) routes of transfer and (iv) the putative functions of microbes in Lepidoptera. To find out whether Lepidopterans possess a core gut microbiome, we com…
Providing insights into browntail moth local outbreaks by combining life table data and semi-parametric statistics
1. Life table studies have been an essential tool for the comprehension of insect population dynamics, although their use has been methodologically biased by a primary focus on mortality factors, especially natural enemies. Thus, studies in natural populations may relegate important mortality sources to the ‘unknown’ or ‘residual’ mortality categories. To overcome this limitation, life tables may be complemented by combining them with other approaches. 2. The aim of the present study was to provide insights into browntail moth Euproctis chrysorrhoea L. (Lepidoptera: Lymantriidae) local outbreaks by combining life table data and statistical modelling. First, E. chrysorrhoea population densit…
Early exposure to predation risk carries over metamorphosis in two distantly related freshwater insects
1. Predation and competition play a central role in ecological communities, and it is increasingly recognised that animals use early warning cues to reduce the impact of these antagonistic interactions. 2. Strategies to avoid risk can occur during embryo development through plasticity in egg hatching time. This strategy, and its associated costs and carryover effects on adults are little understood in insects. In this study, these are explored in two distantly related freshwater insects: the damselfly Ischnura elegans and the mosquito Aedes albopictus. 3. As predicted, damselfly eggs hatched earlier in response to larval predators cues, a treatment that also affected adult size. Risk cues d…
Age and size thresholds for pupation and developmental polymorphism in the browntail moth, Euproctis chrysorrhoea (Lepidoptera: Lymantriidae), under conditions that either emulate diapause or prevent it.
Size and age thresholds for pupation are important life history traits of insects. They are the ultimate consequences of the underlying physiological mechanism that optimize resource allocation. Such thresholds may have a plastic response under time-varying environmental conditions, developmental polymorphism (i.e., plasticity in the number of instars before pupation) being a common strategy adopted by insects to overcome this challenging situation. In this study, we systematically explore the variables related with both age and size thresholds for pupation and developmental polymorphism in the browntail moth, Euproctis chrysorrhoea (Lepidoptera: Lymantriidae), by rearing a group of caterpi…
Hyperparasitism and seasonal patterns of parasitism as potential causes of low top-down control in Euproctis chrysorrhoea (Lymantriidae)
Pest suppression is an important ecosystem service provided by biodiversity, though antagonistic interactions may jeopardize its impact on pest suppression. Hyperparasitoids may release herbivore populations from natural enemy pressure and lead to outbreaks directly due to parasitism as well as indirect through behavioural interference. In a previous study we reported that in native populations of Euproctis chrysorrhoea L. (Lymantriidae) primary parasitism was very low and outbreaks were more likely in coastal habitats than inland. Here we hypothesise that hyperparasitoids are the underlying cause of such patterns by reporting data on direct hyperparasitism rates as well as seasonal pattern…
Description of the final instar of Trichomalopsis peregrina (Hymenoptera, Pteromalidae), with data and comments on the preimaginal stages
The preimaginal stages of T. peregrina are described. The egg displays a sculptured chorion, which is found only on those deposited externally. The immature larvae are characterized by their peculiarities in (a) a setose ring on the thoracic and abdominal segments, (b) an anal notch and (c) size and the sensory structures of the head capsule. The final instar is described and illustrated. Morphological structures of diagnostic value are discussed. The most salient character shown by the mature larva of this species lies in the epistoma, which is complete. Resumen. Se describen las fases de huevo y larva de T. peregrina . El huevo, como es característico en los que se depositan externamente,…