10). Wasps reduced the duration of ventilation movements at higher temperatures (Fig. 9). Total duration of respiration movement events was up to tenfold longer than in honeybees (42.2 vs. 4.8 s at 20 °C, 27.8 vs. 2.3 s at 25 °C; mean values, honeybee data from Kovac et al., 2007). It seems that resting yellow jackets gain their efficient gas exchange to a considerable extent via the length of respiration movements per respiratory cycle. Therefore, they manage a considerably higher RMR (see Käfer et al., 2012) with a similar respiration frequency as honeybees (see Fig. 4). The high respiration volume and efficiency might be responsible for the rather high transition temperature
from discontinuous to cyclic respiration. Despite an overall high level Tofacitinib mw selleck chemical and a steep increase of resting metabolism with increasing ambient temperature (high Q10), resting yellow jackets maintain DGC at comparably high ambient temperatures. They breathe more ‘efficiently’ than other insects, achieving more CO2 emission per
respiration cycle at comparable respiration frequencies. Abdominal ventilation movements at rest were not uniform pumping movements but also included movements of legs antennae and wings, and lateral flipping of the abdomen. Results suggest that respiration efficiency was increased by long duration of these ventilation movements. The research was funded by the Austrian Science Fund (FWF): P20802-B16, P25042-B16. We greatly appreciate the help with electronics by G. Stabentheiner and with data evaluation by M. Bodner, M. Brunnhofer, M. Fink, P. Kirchberger, A. Lienhard, L. Mirwald and A. Settari. We
also thank W. Schappacher for his help in clarifying some quirks with data conversion, two anonymous reviewers for helpful comments and the editor D.L. Denlinger. “
“The defense response to infection in insets is in part mediated by the hemocytes. This cellular response includes phagocytosis, hemocyte aggregation around the invader (nodulation), and formation of a multicellular capsule involving Phospholipase D1 the invader (encapsulation). The cellular response is often accompanied by a humoral response which relies on enzyme cascades for hemolymph coagulation, activation of the phenoloxidase system in hemolymph leading to melanization and production of cytotoxic reactive oxygen species and reactive nitrogen species. In addition, several antibacterial peptides induced by infection in the hemocytes and fat body are secreted into the hemolymph (as reviewed by Gillespie et al., 1997 and Marmaras and Lampropoulou, 2009). The limitations of the immune response due to its physiological cost have been described in insects; indeed, mobilizing available resources to combat infection often comes at the expense of other needs (Schmid-Hempel, 2005). For example, Drosophila females exposed to dead bacteria lay fewer eggs, presumably because resources for egg production are redirected to synthesizing defense molecules ( Zerofsky et al., 2005).