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Army ant invasion of leatherback nests in Gabon

Egg mortality is one of the main factors affecting life history and conservation of oviparous species. A massive and cryptic colonisation of many leatherback turtle (Dermochelys coriacea) eggs is presented in the most important rookery for the species in Gabon. A total of 163 nests were exhumed at Kingere beach, revealing that only 16.7% of eggs produced hatchlings. In the 59% of the nests, more than half of the eggs were dead and attacked by invertebrates and 94% had at least one egg affected by invertebrates. The rate of eggs and SAGs (yolkless eggs) affected by invertebrates within a clutch ranged from 0% to 100%, with an average proportion of 39% and 52%, respectively. The most common invertebrates interacting with the eggs were ghost crabs and insects that affected 51% and 82% of the nests, respectively. Crab and insect co-occurred in 33% of the affected nests. Ants, identified as Dorylus spininodis (Emery 1901) were found in 56% of the excavated nests. However, it was not possible to determine if the ants predated alive eggs or scavenged dead eggs. Very often, hundreds of ants were found drowned within dead eggs. Termites and other invertebrates were associated with the clutch environment and identified as opportunistic feeders, being this is the first record of interaction between termites and sea turtle eggs. An unusual ecological interaction within the leatherback clutches between termites and ants was found in 11% of the nests. The abrupt transition between the soil forest and the beach might be favouring a thriving microbial and invertebrate activity in the sand profile that colonises the nests. informacion[at] Ikaran et al (2020) Cryptic massive nest colonisation by ants and termites in the world's largest leatherback turtle rookery Ethol Ecol Evol 2020. Doi 10.1080/03949370.2020.1715487
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One century of crayfish invasions

One century of crayfish invasions

The red swamp crayfish (Procambarus clarkii), native to the southern United States and north-eastern Mexico, is currently the most widely distributed crayfish globally, as well as one of the invasive species with most devastating impacts on freshwater ecosystems. Reconstructing the introduction routes of invasive species and identifying the motivations that have led to those movements is necessary to accurately reduce the likelihood of further introductions. In this study, the temporal evolution of the scientific literature on the red swamp crayfish was reviewed, georeferenced, time-explicit records of the species to provide a comprehensive understanding of its global expansion process were compiled and the potential role of biological supply companies in the translocations of the red swamp crayfish was evaluated. The interest of the red swamp crayfish in scientific research increased steadily since the beginning of the twentieth century until stabilization in the late 1960s. The number of studies related to the use of the red swamp crayfish in aquaculture showed two peaking periods: the years elapsed between 1970s to mid-1980s, and a continuous increase since the mid-1980s. Research on the red swamp crayfish as an invasive species has only been numerically relevant in recent times, with the number of studies increasing since the 2000s to represent currently around 25% of the scientific production dealing with this species. Although the first introductions of the red swamp crayfish took place in the 1920s, this synthesis highlights the rapid expansion of the species since the 1960s, arguably promoted by the emergence of crayfish industry, but other introduction pathways such as the mitigation of schistosomiasis, potential releases from research experiments, school science programs or pet trade cannot be ruled out. Currently, the red swamp crayfish is present in 40 countries of four continents and there is still potential for further expansion. Commercial suppliers from native (Louisiana) and non-native (California or North Carolina) areas in the United States have provided live-specimens of the red swamp crayfish for scientific research around the world for decades, suggesting that the invasion process of the red swamp crayfish could be more complex than generally assumed. Tracing the introduction routes of invasive species and understanding the motivations that have led to those movements of species is key to reduce their spread and the likelihood of future introductions. informacion[at] Oficialdegui et al (2020) One century away from home: how the red swamp crayfish took over the world. Reviews in Fish Biology and Fisheries DOI: 10.1007/s11160-020-09594-z