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The idea that noncrop habitat enhances pest control and represents a win-win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win-win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies.

The composition of the necrobiome community in the Galapagos Islands is poorly understood, and nothing is known about the dynamics between endemic species and those introduced through human activity.To determine the composition of the carrion fly community, specifically members of the families Muscidae, Calliphoridae and Sarcophagidae, we deployed four kinds of carrion bait traps during the cool and hot seasons at two lowland and two highland sites on Santa Cruz Island within the Galapagos archipelago. We also conducted a laboratory experiment to assess resource competition between fly species encountered in the baiting study.Of the eight fly species found in our baited traps, all were introduced except for the endemic sarcophagid, Sarothromyiops dasycnemis. Four endemic and one native carrion‐feeding species that had been previously recorded on this island were not found. The introduced sarcophagid, Peckia chrysostoma, was the most abundant fly species, comprising over half of the collected specimens, and it was highly dominant at the lowland sites. The endemic species, S. dasycnemis, was only recorded at the lowland sites during the hot season. On the other hand, the calliphorid species were dominant at the highland sites.Experiments demonstrated that P. chrysostoma is a strong competitor against other carrion fly species in the Galapagos necrobiome, including the endemic S. dasycnemis.A comparison of our data with historical records, combined with the results of our laboratory study, leads to the conclusion that introduced carrion fly species, such as P. chrysostoma, represent a threat to endemic carrion fly species, such as S. dasycnemis.Three parasitoid species were reared from 19% of the collected fly puparia. Two of these species attacked fly larvae (Brachymeria podagrica and Aphaereta sp.), whereas one species attacked fly puparia (Exoristobia sp.)We discuss our results in light of the possibility of the purposeful introduction of a parasitoid as a biological control agent against the avian vampire fly (Philornis downsi; Diptera: Muscidae) in Galapagos. [ABSTRACT FROM AUTHOR]

The performance (development and reproduction) of generalist predators can vary greatly among the prey species that they use, and these differences can influence the ability of predatory insects to suppress pest populations. The aim of this study was to compare the performance of larvae of the green lacewing Chrysoperla rufilabris (Burmeister, 1839) by offering 16 species of aphids and by assessing the effects of each species on the survival, larval development time, prey consumption, pupal mass and egg load of adult Chr. rufilabris females taking aphid phylogeny into account. Chrysoperla rufilabris larvae preyed on individuals from all 16 aphid species, but complete development, adult emergence and egg load production were achieved only in seven species. As a general pattern, the best levels of performance were achieved for an aphid clade that includes the soybean aphid, Aphis glycines (Matsumara, 1917), and for a milkweed-feeding species, Myzocallis asclepiadis (Monell, 1879). We found significant phylogenetic clustering for most of the performance traits indicating the aspects of specialization in the diet breadth of Chr. rufilabris despite the fact that this species is considered a generalist aphid predator. These findings can help us to understand the interactions of this species in agroecological food webs, where it is commonly found, and provide insights into why natural, conservation biological control or augmentative releases may succeed or fail. [ABSTRACT FROM AUTHOR]