@article{kirchner_sorenson_blaimer_youngsteadt_2024, title={Reaching new heights: Arboreal ant diversity in a North American temperate forest ecosystem}, ISSN={["1752-4598"]}, DOI={10.1111/icad.12788}, abstractNote={Abstract Most canopy insect research takes place in tropical forests, where communities are highly vertically stratified. However, temperate forest canopies also provide critical resources to many species and are under intense pressure from global change drivers. The relative lack of knowledge regarding temperate canopy insect ecology impedes our forest management and conservation decisions such that we may be losing temperate canopy biodiversity before we know it exists. We directly compared ant diversity and community composition on the ground and in the tree canopy of North American temperate deciduous forests for the first time. We also evaluated two canopy sampling methods—baits and hand collections. We collected 34 ant species from 102 trees across seven sites. Ant diversity was greater on the ground than in the canopy, and species turnover created distinct communities across vertical strata. Only 12% of species were exclusively arboreal, but 47% were collected in both strata, indicating the canopy is an important resource for temperate ants, even if they are not restricted there. Baiting and hand‐collecting recovered similar species richness, but whether baits captured a subset of hand‐collected species or a unique assemblage was site‐dependent. Nevertheless, we suggest that these methods are most effective in conjunction. Hand collection allowed us to document arboreal nests of 10 species, including the invasive needle ant, Brachyponera chinensis , which was previously thought to be strictly terrestrial. Our results emphasise the importance of including the canopy in temperate forest ecology and conservation assessments.}, journal={INSECT CONSERVATION AND DIVERSITY}, author={Kirchner, Michelle and Sorenson, Clyde and Blaimer, Bonnie B. and Youngsteadt, Elsa}, year={2024}, month={Nov} }
 @article{kirchner_bertone_blaimer_youngsteadt_2023, title={COLONY STRUCTURE AND REDESCRIPTION OF MALES IN THE RARELY COLLECTED ARBOREAL ANT, <i>APHAENOGASTER</i> <i>MARIAE</i> FOREL (HYMENOPTERA: FORMICIDAE)}, volume={125}, ISSN={["0013-8797"]}, DOI={10.4289/0013-8797.125.1.77}, abstractNote={Abstract. Aphaenogaster mariae Forel is a rarely encountered North American arboreal ant that has eluded collectors for decades. Here, we provide the first formal documentation of a whole colony collection of the species found seventeen meters high in the canopy of the North Carolina Piedmont. We discovered a mature colony with more than 1000 individuals, including workers, alate reproductives, immatures, and intercastes. We present the first images of the males, larvae, pupae, and intercaste workers, redescribe the male, and provide natural history insights and colony demographics for this elusive species. Our collections suggest that A. mariae occurs at low densities consistent with its putative socially parasitic life history. Although much remains to be learned about this species, our results expand knowledge of its life history and facilitate future nest discovery and identification.}, number={1}, journal={PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON}, author={Kirchner, Michelle and Bertone, Matthew and Blaimer, Bonnie B. and Youngsteadt, Elsa}, year={2023}, month={Jan}, pages={77–88} }
 @article{youngsteadt_prado_keleher_kirchner_2023, title={Can behaviour and physiology mitigate effects of warming on ectotherms? A test in urban ants}, ISSN={["1365-2656"]}, DOI={10.1111/1365-2656.13860}, abstractNote={Abstract


Global climate change is expected to have pervasive effects on the diversity and distribution of species, particularly ectotherms whose body temperatures depend on environmental temperatures. However, these impacts remain difficult to predict, in part because ectotherms may adapt or acclimate to novel conditions or may use behavioural thermoregulation to reduce their exposure to stressful microclimates.

Here we examine the potential for physiological and behavioural changes to mitigate effects of environmental warming on five species of ants in a temperate forest habitat subject to urban warming.

We worked in eight urban and eight non‐urban forest sites in North Carolina, USA; sites experienced a 1.1°C range of mean summer air temperatures. At each site, we documented species‐specific microclimates (ant operative temperatures, Te) and ant activity on a transect of 14 bait stations at three times of day. In the laboratory, we measured upper thermal tolerance (CTmax) and thermal preference (Tpref) for each focal species. We then asked whether thermal traits shifted at hotter sites, and whether ants avoided non‐preferred microclimates in the field.

CTmax and Tpref did not increase at warmer sites, indicating that these populations did not adapt or acclimate to urban warming. Consistent with behavioural thermoregulation, four of the five species were less likely to occupy baits where Te departed from Tpref. Apparent thermoregulation resulted from fixed diel activity patterns that helped ants avoid the most inappropriate temperatures but did not compensate for daily or spatial temperature variation: Hotter sites had hotter ants.

This study uses a novel approach to detect behavioural thermoregulation and sublethal warming in foraging insects. The results suggest that adaptation and behaviour may not protect common temperate forest ants from a warming climate, and highlight the need to evaluate effects of chronic, sublethal warming on small ectotherms.

}, journal={JOURNAL OF ANIMAL ECOLOGY}, author={Youngsteadt, Elsa and Prado, Sara Guiti and Keleher, Kirsten Joanna and Kirchner, Michelle}, year={2023}, month={Jan} }