The Yellow-legged Hornet (Vespa velutina nigrithorax) (YLH) is an invasive insect that arrived in Europe in 2004 and is now spread across nine countries. It is a threat to the native entomofauna and harmful to beekeeping and agriculture, as it is a ravenous predator of the European Honey Bee (Apis mellifera) and other pollinating species. Its expansion has been unstoppable and all resources are needed to fight against it, including native vertebrate predators. Among these, the European Bee-eater (Merops apiaster) (EBE) is a potential one, but little is known about its predation on YLH. In a study carried out in Portugal, remains of YHL were detected in EBE nesting sites, which, to the best of our knowledge, is the first such report. This means that this bird could be one more agent in the biological control of this pest (although research on predation intensity is still needed), in conjunction with other natural predators and other strategies. In the Iberian Peninsula, both species are allopatric in vast regions, so the role of EBE may be more limited. However, in the rest of Europe, at a country or continent scale, the scenario may be different and sympatry may occur to a greater extent.
Neste artigo fazemos uma revisão dos predadores vertebrados naturais da Vespa-asiática (Vespa velutina) na Europa e em Portugal em particular, enumerando aqueles para os quais já existem observações comprovadas e aqueles que, por se alimentarem da Vespa-europeia (Vespa crabro), mesmo que irregularmente, podem ser considerados consumidores potenciais da primeira. Damos particular atenção ao Vespeiro (Pernis apivorus) e ao Abelharuco (Merops apiaster), por serem potencialmente os predadores vertebrados mais importantes da Vespa-asiática, seja porque são especialistas em insectos da subordem Apocrita -que inclui as vespas, abelhas e formigas -, seja porque para eles existe considerável informação sobre a sua ecologia trófica. Fruto de um estudo realizado em 2021, os resultados confirmam que o Abelharuco captura Vespa-asiática, mas desconhecemos ainda quão importante é este consumo. Embora a Abelha-europeia (Apis mellifera) seja a espécie mais frequente nos restos de presas colhidos, a dieta desta ave aparenta ser diversa.
The diet of Short-toed Snake-eagle (Circaetus gallicus) during the breeding season in an area dominated by cork and holm oak parkland forests (Montados) was analyzed in this study. As expected, results showed that snakes are the dominant prey in the diet of this eagle, comprising up to 92.5% of the identified items, if potential secondary prey species were excluded. The Montpellier Snake (Malpolon monspessulanus) was the most consumed one (42.2%), followed by the Ladder Snake (Zamenis scalaris) (28.0%), and the water snakes (Natrix spp.) (14.2%). According to the same criteria, lizards (mainly Psammodromus algirus) and mammals represent between 4.8 and 2.2%, respectively. Other animals such as pond turtle and amphibians are irregular prey (<1%), and no bird remains were found at all. Short-toed Snake-eagle is usually referred as a stenophagic predator where snakes are by far its most important prey type, and where within this taxonomic group it behaves as a generalist predator. In this study this premise was then tested comparing the relative abundance of the snake species with their proportion in the diet composition of the eagle in order to know whether or not prey selection exists with regard to the species of snakes in this region. Results point to a quite plausible "preference" for the Ladder Snake and an "avoidance" for the smooth snakes group (Macroprotodon brevis/Coronella girondica), and possibly for the Horseshoe Whip (Hemorrhois hippocrepis). The avoidance to the Horseshoe Whip must be indirect and habitat related, while in relation to the two smooth snakes it may be due in large extend to its small size, in particular.
The Yellow-legged Hornet (Vespa velutina nigrithorax) (YLH) is an invasive insect that arrived in Europe in 2004 and is now spread across nine countries. It is a threat to the native entomofauna and harmful to beekeeping and agriculture, as it is a ravenous predator of the European Honey Bee (Apis mellifera) and other pollinating species. Its expansion has been unstoppable and all resources are needed to fight against it, including native vertebrate predators. Among these, the European Bee-eater (Merops apiaster) (EBE) is a potential one, but little is known about its predation on YLH. In a study carried out in Portugal, remains of YHL were detected in EBE nesting sites, which to the best of our knowledge is the first such report. This means that this bird could be one more agent in the biological control of this pest (although research on predation intensity is still needed), in conjunction with other natural predators and other strategies. In the Iberian Peninsula both species are allopatric in vast regions, so the role of EBE may be more limited. However, in the rest of Europe, at a country or continent scale, the scenario may be different and sympatry may occur to a greater extent.
Data on Montagu’s Harrier biology was gathered in 1992 during a broader survey on birds of prey in the region of Castro Verde, during which pellets and prey remains were harvested in order to study their diet. Main land-use of the study area was extensive cereal crops with fallow fields. A total of 143 pellets collected in perches were analyzed and 1351 items were counted. Invertebrates were the main prey in number (97.2%) and biomass (32.9%). Birds and mammals were also important prey in terms of biomass (30.2 and 28%, respectively), despite its low numbers in relation to all identified prey (4.3 and 1.3%, respectively). Prey weighing less than 30 g were the most frequent (98.1%) with a corresponding biomass of around 62.1%. For prey weighing more than 100 g only Lagomorphs contributed to it, totaling 25% in terms of biomass, despite their remarkably low numbers (0.4% of total prey). This high predation on invertebrates while low on mammals agrees, with the known latitudinal trends of diet composition of the Montagu’s Harrier, and some other birds of prey, along the Palearctic. In this part of Iberia, where large orthopterans are particularly common in extensive cereal fields, strong presence of insects was found in the diet of Montagu’s Harrier populations. This feature seems to be related to the abundance of orthopterans in southern Europe.