Know thy enemy: interspecific differences of pine consumption among leafcutter ants in a plantation

Abstract

The damage to plantations by pests is often determined by perceptions rather than objective data, resulting in excessive use of pesticides. Leafcutter ants are considered important pests to plantations in America. We evaluated the difference in Pinus taeda biomass consumption by four Acromyrmex leafcutter ant species which co-inhabit plantations of this pine species. These ants exhibit morphological and behavioral differences, i.e., Ac. heyeri has mandibles adapted to cut monocots, while the other species cut dicots, which may result in differences in their consumption of pine. We collected the plant biomass that ants carried into their nests and recorded the foraging activity in different seasons throughout a year. The P. taeda biomass carried into leafcutter nests was less than 20 % compared to total plant biomass. Colonies with greater foraging activity carried a greater amount of total biomass, but they did not carry more pine biomass. The leafcutter ant species studied differed in their use of pine biomass, but not of total biomass. Acromyrmex ambiguus and Ac. crassispinus were the species carrying the greatest amount of pine biomass and with more colonies using pine, whereas very little amounts of pine were carried by Ac. heyeri and by very few colonies. Thus, leafcutter ant species do not cause the same damage to pine plantations. Our results also highlight the importance of pest management strategies based on a thorough knowledge of the biology of the species, including those characteristics which can predict the use that each species will make of the plantation.

Biological control of leaf‐cutter ants using pathogenic fungi: experimental laboratory and field studies

“…We found variation in consumption, which was not surprising given the amount of variation shown in activity levels among colonies in this study. Furthermore, the fact that it took more time for the second set to be carried away, in comparison to the first one, is consistent with the notion that ants forage less when temperatures are low (Bernstein, 1979; Elizalde et al., 2016). Regarding the F3 of the third set, a non‐recorded abiotic variable may have affected the consumption, as this was also lower for the controls placed simultaneously.…”

“…However, a few indirect estimates have been made, especially for the forestry sector. Between 10 and 25% of Pinus or Eucalyptus plants are lost due to LCA attacks (Amante, 1967; Reis Filho et al., 2011) and the diameter and height of pine seedlings during the first 2 years decreased significantly in comparison to plants not attacked (Cantarelli et al., 2008; Elizalde et al., 2016). It was estimated that more than 50% of Eucalyptus wood production can be lost due to LCA attacks (Zanetti et al., 2003; Oliveira et al., 2011).…”

Leaf‐cutting ant abundance and distribution under different agricultural practices in grassland biome

“…Also, other mechanisms related to human manipulation of commercial crops have been proposed to explain that LCA proliferation as, for example, LCA workers preferred foraging on plants fertilized with nitrogen and phosphorus-based fertilizers (Nichols-Orians, 1991). The causes of LCA proliferation, their foraging preferences and their distribution have been widely studied for the forest biome (Vasconcelos & Cherrett, 1995;Bollazzi et al, 2008;Barrera et al, 2015;Elizalde et al, 2016), but a gap still exists about their responses in other biomes (Siqueira et al, 2017). Particularly, in grassland biomes, agricultural practices and forestry have been shown to reduce pioneer vegetation and to create closed habitats due to the use of herbicides or the introduction of vertical strata (Bremer & Farley, 2010;Gerstner et al, 2014;Santoandré et al, 2019a).…”

Potential damage by Acromyrmex ant species in pine plantations in southern Brazil

“…Economic losses associated with attacks by these ants can also be minimized by recognizing their potential impact. For instance, one study showed differences in P. taeda biomass intake among four Acromyrmex leaf‐cutting ant species in a pine plantation in Argentina (Elizalde et al ., 2016).…”