Using insect traps to increase weaver ant (Oecophylla longinoda) prey capture

Abstract

Weaver ants (Oecophylla spp.) are managed in plantations to control insect pests and are sometimes harvested as a protein‐rich food source. In both cases, the amount of insect prey caught by the ants is imperative for returns, as more prey leads to more effective biocontrol and to a higher production of ants. Malaise‐like traps placed in trees may catch flying insects without catching ants, as ants may use pheromone trails to navigate in and out of the traps. Thus, ants may increase their prey intake if they are able to extract insects caught in traps. In a mango plantation in Tanzania, we estimated the amount of insects caught by simple traps (cost per trap = 3.9 USD), and whether Oecophylla longinoda was able to collect insects from them. On average, a trap caught 110 insects per month without catching any weaver ants. The number of insects found in traps with ant access was 25% lower than in control traps (ants excluded), showing that ants were able to gather prey from the traps. Ant activity in traps increased over time, showing that prey extraction efficiency may increase as ants customize to the traps. The prey removed from traps by ants constituted 5% of the number of prey items collected by O. longinoda under natural conditions (without traps), potentially increasing to 14% if ants learn to extract all insects. Thus, prey intake may be increased with 5–14% per 3.9 USD invested in traps. These numbers increased to 38 and 78%, respectively, when light was used to attract insects during night time. Combining ant predation with insect trapping is a new approach potentially building increased returns to ant biocontrol and to ant entomophagy.

DNA Metabarcoding Enables High-Throughput Detection of Spotted Wing Drosophila (Drosophila suzukii) Within Unsorted Trap Catches

“…These ants may have entered traps to prey on already collected insects and would have been able to safely exit those traps which solely relied upon flying insects drowning in the attractant solution. Predation of trapped specimens by ants and spiders has been documented previously (Armstrong and Richman, 2007;Lynegaard et al, 2014), and raises an intriguing question about whether predation could be an additional source of false negatives for biosecurity surveillance programs.…”

The dynamics of ant mosaics in tropical rainforests characterized using the Self‐Organizing Map algorithm

“…Because TDAs protect their host trees through their predatory behavior and/or by deterring defoliating insects (Room, ; Taylor, ; Way & Khoo, ; Majer, ; Dejean et al ., ) or because they displace ground‐nesting, arboreal‐foraging ant species (Taylor & Griffin, ; Kenne et al ., ), certain of them are recognized as potential biological control agents. Others, particularly Oecophylla spp., are already used to protect orchards from defoliators or fruit parasites (Huang & Yang, ; van Mele et al ., , ; Offenberg et al ., ; Lynegaard et al ., ).…”

The search rate of the African weaver ant in cashew

“…However, this aggregated response only seems to apply to larger prey items that cannot be carried by one or a few ants, and does therefore not apply to our situation where single or a few ants were observed to carry the food items. Most O. longinoda prey items are smaller insects that can be carried by single ants (Lynegaard et al, 2014). On the other hand, situations where the ants generally feed on larger food items such as larger beetles, cockroaches, dragon flies, larger moths, butterflies, lizards or dead mammals may occur, and in such cases aggregated responses can be expected and the assumptions behind the Nicholson-Bailey equation fail.…”