The global spread and invasion capacities of alien ants

The pyrexia channel remodels egg-laying of Liriomyza huidobrensis in response to temperature change

BACKGROUND

The pea leafminer, Liriomyza huidobrensis, is one of the most important insect pests on vegetables and ornamentals. The survival and egg-laying behavior of leafminers are markedly affected by the environment temperature. However, the mechanisms underlying the relationship between egg-laying and temperature are still largely unknown.

RESULTS

Here, we find that leafminers have evolved an adaptive strategy to overcome the stress from high or low temperature by regulating oviposition-punching plasticity. We further show that this oviposition-punching plasticity is mediated by the expression of pyx in the ovipositor when subjected to disadvantageous temperature. Specifically, down-regulation of pyx expression in leafminers under low temperature stress led to a significant decrease in the swing numbers of ovipositor and puncture area of the egg spot, and consequently the lower amount of egg-laying compared to leafminers at ambient temperature. Conversely, activation of pyx expression under high temperature stress increased the swing numbers and puncture area, still resulting in a reduction of egg-laying amount.

CONCLUSION

Thereby, leafminers are able to coordinate pyx channel expression level and accordingly depress the oviposition. Our study uncovers a molecular mechanism underlying the adaptive strategy in insects that can avoid disadvantageous temperature for reproducing offspring. © 2024 Society of Chemical Industry.

Non-native ants are breaking down biogeographic boundaries and homogenizing community assemblages

As geographic distance increases, species assemblages become more distinct, defining global biogeographic realms with abrupt biogeographic boundaries. Yet, it remains largely unknown to what extent these realms may change because of human-mediated dispersal of species. Focusing on the distributions of 309 non-native ant species, we show that historical biogeographic patterns have already broken down into tropical versus non-tropical regions. Importantly, we demonstrate that these profound changes are not limited to the distribution patterns of non-native ants but fundamentally alter biogeographic boundaries of all ant biodiversity (13,774 species). In total, 52% of ant assemblages have become more similar, supporting a global trend of biotic homogenization. Strikingly, this trend was strongest on islands and in the tropics, which harbor some of the most vulnerable ecosystems. Overall, we show that the pervasive anthropogenic impacts on biodiversity override biogeographic patterns resulting from millions of years of evolution, and disproportionally affect particular regions.

Response to Genovesi et al.: Ant biosurveillance should come before invasion

Menchetti et al. respond to the letter of Genovesi et al. and contribute new records of the red imported fire ant in Sicily.

Non-native ants drive dramatic declines in animal community diversity: A meta-analysis

Non-native ants can cause ecosystem-wide ecological change, and these changes are generally assumed to be negative. Despite this, the evidence base has never been holistically synthesised to quantify whether and to what degree non-native ants impact native species diversity.In this study, we performed a meta-analysis of the effects of ant invasion on animal communities. We extracted data from 46 published articles investigating abundance (156 effect sizes) and richness (53 effect sizes) responses of animal taxa to ant invasion in locations relatively unimpacted by other stressors (e.g. human disturbance, other non-native species) to help isolate the effects of invasion.Overall, local animal diversity declined severely, with species abundance and richness lower by 42.79% and 53.56%, respectively, in areas with non-native ants compared with intact uninvaded sites. We then combined responses of individual animal taxa extracted from an article into a single response to represent the 'community' abundance (40 effect sizes) or richness (28 effect sizes) response to non-native ants represented in each article. Local communities decreased substantially in total abundance (52.67%) and species richness (53.47%) in invaded sites.These results highlight non-native ants as the drivers, rather than passengers, of large net-negative reductions to animal community diversity in relatively undisturbed systems around the world, approximately halving local species abundance and richness in invaded areas. Improved international prevention processes, early detection systems harnessing emerging technologies, and well-designed control measures deployable by conservation practitioners are urgently needed if these effects are to be mitigated, prevented or reversed.

Generalized mutualisms promote range expansion in both plant and ant partners

Mutualism improves organismal fitness, but strong dependence on another species can also limit a species' ability to thrive in a new range if its partner is absent. We assembled a large, global dataset on mutualistic traits and species ranges to investigate how multiple plant-animal and plant-microbe mutualisms affect the spread of legumes and ants to novel ranges. We found that generalized mutualisms increase the likelihood that a species establishes and thrives beyond its native range, whereas specialized mutualisms either do not affect or reduce non-native spread. This pattern held in both legumes and ants, indicating that specificity between mutualistic partners is a key determinant of ecological success in a new habitat. Our global analysis shows that mutualism plays an important, if often overlooked, role in plant and insect invasions.

The invasive ant Solenopsis invicta is established in Europe

The red imported fire ant (Solenopsis invicta) is classified as one of the worst invasive alien species1 and as the fifth costliest worldwide2, impacting ecosystems, agriculture and human health3. We report the establishment of S. invicta in Europe for the first time, documenting a mature population in Sicily. We use genetic analyses to assess its putative origin, as well as wind tracking and species distribution modelling to predict its potential range on the continent. We show that half of the urban areas in Europe are already suitable and that climate warming expected under current trends will favor the expansion of this invasive ant.

Biological invasions: The secret domination of alien ants

Globalization has contributed to the spread of thousands of species, yet only a few harmful ones have attracted most attention. New evidence shows that introduced ants are a particularly important group of global invaders that can dominate native insect communities.

The unusual genetics of invasive ants

The males of an invasive ant species are chimeras of two distinct genetic lineages.