Ants in citrus: impact on the abundance, species richness, diversity and community structure of predators and parasitoids

Abstract

Although ants act as plant biotic defences, in agricultural ecosystems they are often associated with outbreaks of honeydew-producing pests mainly due to the protection they offer to the plant feeders in exchange for honeydew. In such an interaction ants may alter the abundance, diversity and community structure of predators and parasitoids. In the present study, we conducted ant-exclusion experiments in three commercial citrus orchards, each one dominated by one ant species (Pheidole pallidula, Lasius grandis or Linepithema humile) during two consecutive years (2011 and 2012). We then compared the abundance, species richness, diversity and community structure of predators and parasitoids between the antallowed and ant-excluded treatments. A total of 176,000 arthropods belonging to 81 taxa were captured and identified. Regarding abundance, our results showed a species specific response between treatments. When examining functional groups, in the ant-allowed treatment, seven species of predators decreased and four increased in abundance, whereas four species of parasitoids decreased and 18 increased in abundance. The species richness (S) was significantly lower for predators and higher for parasitoids in the ant-allowed treatment. The Shannon diversity index (H) was not different between treatments in the case of predators, whereas in the case of parasitoids diversity was significantly higher in the antallowed treatment. Finally, the community structure of predators and parasitoids was not significantly different between treatments. These results suggest that ants in the citrus agroecosystem are not associated with a dramatic decrease in natural enemy abundance or biodiversity; on the contrary ants were associated with increased parasitoid species richness and diversity. Despite the fact that ants have no negative impact on the abundance and diversity of predators and parasitoids at the community level their impact on specific natural enemy species, mainly predators, may explain the highest pest densities associated with ants in citrus.

The impact of ant mutualistic and antagonistic interactions on the population dynamics of sap‐sucking hemipterans in pear orchards

“…In this case, P. gallicus was found to prey on both psyllids and aphids but predation was greatly reduced in the presence of ants. These observations are in agreement with the ant– P. gallicus negative interaction registered in the field, but in contrast with the positive correlation reported by other authors . Evidence of ant avoidance behaviour, such as spatial segregation, was found in spiders from the analysis of field data.…”

“…These observations are in agreement with the ant-P. gallicus negative interaction registered in the field, but in contrast with the positive correlation reported by other authors. 69,70 Evidence of ant avoidance behaviour, such as spatial segregation, was found in spiders from the analysis of field data. Other authors have also reported spatial segregation of ants and spiders.…”

Development of an alginate hydrogel to deliver aqueous bait for pest ant management

“…Hemipteran honeydew is an important nutrient source for Argentine ants, and the presence of Argentine ants harvesting honeydew protects hemipteran pests from natural enemies . Thus, effective Argentine ant management in agricultural environments is necessary to maximize the effectiveness of natural enemies attacking plant pests …”

Can the absence of ants interfere in the arthropods abundance on corn plants (Zea mays L. - Poaceae)?

“…According to the results of this Other study showed that Dermaptera of genus Dorus are efficient herbivorous predators in corn monoculture (see Cruz 1991). Additionally, Buschman et al (1977) Some studies have shown that the result of ant-plant interaction is dependent of the species of predatory ants involved interaction (Byk & Del-Claro, 2010;Calabuig et al, 2015) and of the strategies of herbivorous against predation (Bächtold & Alves-Silva, 2013;Carita et al, 2006;Styrsky & Eubanks, 2010). Nevertheless, little is known about the behavior between pairs (predator-prey) determining plant protection.…”

“…Elements such as ant species features (Byk & Del-Claro, 2010;Calabuig et al, 2015), their density (De la Mora et al, 2015) and also herbivorous defense strategy against predation (Bächtold & Alves-Silva, 2013) however, some species may be more influenced than others.…”