Improving insect mass-rearing practice for food and feed
Abstract The rarity of parthenogenetic species is typically attributed to the reduced genetic variability that accompanies the absence of sex, yet natural parthenogens can be surprisingly successful. Ecological success is often proposed to derive from hybridization through enhanced genetic diversity from repetitive origins or enhanced phenotypic breadth from heterosis. Here, we tested and rejected both hypotheses in a classic parthenogen, the diploid grasshopper Warramaba virgo. Genetic data revealed a single hybrid mating origin at least 0.
Temperature affects biological processes on many levels of biological organisation
Abstract Insect life cycles are adapted to a seasonal climate by expressing alternative voltinism phenotypes—the number of generations in a year. Variation in voltinism phenotypes along latitudinal gradients may be generated by developmental traits at critical life stages, such as eggs. Both voltinism and egg development are thermally determined traits, yet independently derived models of voltinism and thermal adaptation refer to the evolution of dormancy and thermal sensitivity of development rate, respectively, as independent influences on life history.
Abstract The phenological response is among the most important traits affecting a species' sensitivity to climate. In insects, strongly seasonal environments often select for a univoltine life-cycle such that one seasonal extreme is avoided as an inactive stage. Through understanding the underlying mechanisms for univoltinism, and the consequences of its failure, we can better predict insect responses to climate change. Here we combine empirical data and simulation studies to investigate the consequences of an unusual diapause mechanism in a parthenogenetic matchstick grasshopper, Warramaba virgo, from arid southern Australia.
Abstract Mechanistic models of the impacts of climate change on insects can be seen as very specific hypotheses about the connections between microclimate, ecophysiology and vital rates. These models must adequately capture stage-specific responses, carry-over effects between successive stages, and the evolutionary potential of the functional traits involved in complex insect life-cycles. Here we highlight key considerations for current approaches to mechanistic modelling of insect responses to climate change. We illustrate these considerations within a general mechanistic framework incorporating the thermodynamic linkages between microclimate and heat, water and nutrient exchange throughout the life-cycle under different climate scenarios.
Abstract High-throughput genomic methods are increasingly used to investigate invertebrate thermal responses with greater dimensionality and resolution than previously achieved. However, corresponding methods for characterizing invertebrate phenotypes are still lacking. To scale up the characterization of invertebrate thermal responses, we propose a novel use of thermocyclers as temperature-controlled incubators.
Here, we tested the performance of thermocyclers as incubators and demonstrated the application of this method to efficiently characterize the thermal responses of model and non-model invertebrates.