J. Ellers

Lipids are an important class of nutrients for insects, as they are the main energy source during metamorphosis and crucial for survival and reproduction. Lipid reserves in insects are mostly accumulated during larval development and can be influenced by environmental factors such as diet and temperature. Genetic factors can also affect larval lipid content and composition. Larvae of the house fly, Musca domestica L. (Diptera: Muscidae), are a valuable emerging resource for the insect feed sector, fueling a growing interest in the factors regulating larval lipid content. We investigated whether strains of three geographical origins vary in ontogeny, quantity, and composition of stored lipids in response to temperature. Italian, Spanish, and Dutch house fly larvae were reared on a similar diet at 25 and 35 °C. Larval dry weight and total lipid content were determined in early‐, mid‐, and late‐third instars by extraction of soluble lipids. The fatty acid composition was analyzed in late‐third instars using an improved extraction and derivatization protocol. We found that strain, larval stage, and temperature affected larval dry weight and absolute and relative lipid content, with significant interaction effects between these three factors. All flies were reared in a common environment, indicating a genetic component to lipid storage. Analysis of lipid composition identified 11 fatty acids, including some rarely reported in the literature. Five fatty acids accounted for 80 and 81% of the total fatty acid methyl esters detected at 25 and 35 °C, respectively. An effect of temperature but not strain was evident on the composition of the fatty acids. The observed differences in lipid content among strains and temperature conditions could be of interest for commercial rearing of the house fly.

Aim Island biogeography theory states that species richness increases with habitat diversity and decreases with isolation from source pools. However, ecological theory must incorporate effects of human activity to explain contemporary patterns of biodiversity. We contemporized island biogeography theory by conceptualizing island trajectories of how species richness changes over time with accelerating land development and economic trade, which increase extinction and immigration rates, respectively. With this contemporized theory, we then articulate and empirically assess expected relationships of native, introduced and total species richness with natural and anthropogenic metrics of habitat diversity and isolation from source pools. Location Greater Caribbean region. Time period Database finalized in 2020. Methods We built a database of 1,042 native and introduced reptiles and amphibians (herps) for 840 Caribbean islands. For each island, we calculated natural and anthropogenic metrics of island habitat diversity and isolation from source pools and used linear model averaging to assess the expected relationships under the contemporized theory for 15 major herp clades. Results Natural habitat diversity metrics exhibited positive relationships with native and introduced species richness, strengthening total species richness–area relationships across herp clades. Geographic isolation exhibited negative relationships with native and positive relationships with introduced species richness, weakening total species richness–isolation relationships. Economic area, based on developed land, and economic isolation, based on maritime trade, exhibited negative relationships with native species richness, but positive and negative relationships, respectively, with introduced species richness. Total species richness relationships with these two anthropogenic metrics were strongest in clades with many introduced species. Main conclusions A contemporized island biogeography theory that includes the effects of land development and economic trade on species extinction and immigration explained current Caribbean herp species richness patterns. As human activity continues to accelerate, the contemporized theory we articulate here will increasingly predict island biogeography of the Anthropocene.