Image of the assassin bug attacking a caterpillar / sur

The assassin bug, the latest invasive species found in Malaga

GENA-Ecologists in Acción warns of the discovery of specimens of Zelus renardii in Torre del Mar two years after the entomologist Manuel Baena detected them for the first time in Alhaurín de la Torre

Eugenio Cabezas

The environmental group GENA-Ecologistas en Acción has sent a letter to the Ministry of Ecological Transition and the Regional Ministry of the Environment explaining that a specimen of the so-called assassin bug, whose scientific name is Zelus renardii (Kolenati, 1857), has been found in Torre del Mar.

The insect is part of the Hemiptera family, which is made up of bugs with "sucking biting" mouthparts, which includes field bugs, "but this one belongs to the Reduviidae family, which are carnivorous species which preys on other insects," explained biologist and president of GENA, Rafael Yus.

This species does not eat its prey because of its mouthparts, but instead "sucks the internal organs and fluids of the prey, causing it to die", he added. Hence the name assassin bug. "It does not cause any harm to humans," Yus pointed out.

It is native to North America and has probably come into Spain accidentally, possibly with a plant from the region. "This is the usual way in which numerous exotic species enter and it wouldn’t matter so much if it wasn’t a predator, feeding on other insects, including native species, which control pests or play an important role in the balance of complex trophic networks", argued Yus.

As the biologist and entomologist describes, "Given that this species does not seem to have preferred prey, is polyphagous or non-specific, the risk of it becoming an invasive species is very high, so it may have to be upgraded from alien to invasive species status." However, Yus added that it could also have a beneficial effect, as it has a special predilection for aphids, many of which become pests, therefore becoming an ally for the farmer or gardener," he explained.

First recorded in Murcia in2010

The first record of the assassin bug in Spain was noted in Murcia in 2010 by Luis Vivas, who identified it in photographs of specimens photographed in Monteagudo (Murcia), in photos taken in 2010 by a German, Klaus Kamppeter. In Malaga it was identified for the first time by the entomologist Manuel Baena in Alhaurín de la Torre in 2019.

This insect has been reported to occasionally sting humans and those who have been stung say that they produce an intense, sharp pain that can last for several minutes or even hours before disappearing. There is no specific season for stinging and stings have been reported both outdoors and indoors. Researchers suggest that "they may be attracted to humans when they move.”

Researchers Adrià Miralles-Núñez, Carlos Pradera and Juan A. Pujol, published last April a paper compiling nine cases of stings in Spain since 2018. Almost all had occurred in Valencia, although one was counted in Cadiz and another in Alcalá de Henares. However, research has shown that the insect does not feed on human blood but "can accidentally bite people, causing acute pain that subsides within a few hours, but without having been shown to transmit any disease".