Ant Occupation of Twigs in the Leaf Litter of the Atlantic Forest: Influence of the Environment and External Twig Structure

Abstract

Twig cavities are microhabitats that may be used by different ant species for nesting and colony expansion. However, ants do not colonize all twigs available in the leaf litter, pointing to the existence of environmental or twig-related filters. In this study, we analyzed which environmental and twig attributes affected twig occupation by ants. We surveyed seven plots in six Atlantic forest sites in southeastern Brazil. To characterize the environmental filters, we quantified canopy cover and leaf litter moisture and depth. At the twig level, we measured twig length and diameter and the area and circumference of all holes in each twig. Ant colonies occupied 13.42% of the 4,805 twigs surveyed, and we recorded a total of 52 twig-nesting ant species. Brachymyrmex admotus was the most frequent species. Ant species richness increased with canopy cover and leaf litter moisture and with the relative number of occupied twigs. In addition, we found that ant species richness increased with length and diameter of the twigs, and that twigs with smaller holes were more frequently occupied by ants, regardless of the availability of larger diameter holes. Our work demonstrates that both environmental characteristics and twig morphology can structure occupation of twigs by ants. In addition, we demonstrated that certain species show a preference for certain twig types. We highlight the importance of twigs for maintaining ant diversity and for colony expansion of arboreal species and species inhabiting the leaf litter.

Occurrence of Pheidole tijucana Borgmeier, 1927 (Hymenoptera, Formicidae) in the state of São Paulo, Brazil

“…Since the description of P. tijucana, many surveys of leaf litter have been carried out in the Brazilian Atlantic Forest (i.e., Delabie et al 2007;Pacheco et al 2009;Suguituru et al 2011Suguituru et al , 2013Silva et al 2022), including in wood structures that are colonized by species of Pheidole (Souza et al 2012;Fernandes et al 2019Fernandes et al , 2020. Moreover, several surveys have also been made in urban areas of Brazil (Bueno et al 2017), and P. tijucana has not been recorded in any of them.…”

“…Nesting and foraging occur mainly in deeper soil layers, or above or between the interstices of the leaf litter (Delabie et al 2000;Casadei-Ferreira 2021). In the leaf litter, Pheidole may occupy fruits, seeds, and wood in varying degrees of decomposition (Castaño-Menzes et al 2015;Casadei-Ferreira 2021), and the latter includes twigs (Fernandes et al 2019). Barroso et al (2020) and Almeida et al (2021) suggested that the occupation of twigs by species of Pheidole could be due to a process of selection.…”

The Importance of Forest Simplification and Litter Disturbance in Defining the Assembly of Ground-Foraging Ants

“…Our results corroborate other findings wherein ant communities were negatively affected by anthropogenic impacts that result in habitat simplification, such as fire (Costa et al 2018), fragmentation (Underwood & Fisher 2006), urbanization (Oliveira et al 2017), and litter clearance (Paolucci et al 2010). Several studies have suggested that litter heterogeneity is determinant for ants that forage on tropical forest ground (e.g., Brühl et al 2003, Pacheco et al 2009, as it represents greater opportunities for nesting sites and higher resource availability (e.g., prey), enabling a more diverse fauna (Byrne 1994, Fernandes et al 2019. For instance, Paolucci et al (2010) showed that after an experimental litter removal event with subsequent natural recovery, increases in litter amount were correlated with increases in ant richness.…”

Serapilheira em floresta Atlântica no Brasil: uma abordagem da produção científica (1987-2019)

“…Entre as principais temáticas abordadas destacaram-se os estudos com a macrofauna edáfica (101 abordando a diversidade, endemismo, colonização, predação e distribuição de artrópodes na serapilheira (Freitas et al, 2014;Meloni & Varanda, 2015;Lira et al, 2016;Amaral et al, 2019). Dentre os grupos de artrópodes mais representativos, apontados nos estudos, destacaram-se as aranhas (Huber, 2016(Huber, , 2018, os besouros (Braun et al, 2018;Salomão et al, 2019), as formigas (Oliveira, M. V. et al, 2018;Fernandes et al, 2019aFernandes et al, , 2019b, os gafanhotos (Pereira et al, 2010), os crustáceos terrícolas (Bugs et al, 2014), os cupins (Araújo et al, 2016;Almeida et al, 2017) e os escorpiões (Lira et al, 2017;Dionisio-da-Silva et al, 2018).…”