Jh. Hunt et al., Observations on two neotropical swarm-founding wasps, Agelaia yepocapa andA-panamaensis (Hymenoptera : Vespidae), ANN ENT S A, 94(4), 2001, pp. 555-562
In north western Costa Rica, Agelaia yepocapa (Richards) nests in cavities
within living hollow trees in lower montane mesic forests; A. panamaensis (
Cameron) nests in very large cavities in premontane gallery forests. Nests
of both species have vertical combs with horizontal cells that face outward
from the nest center: the nests have no enclosing envelope. In January 199
6, an A. yepocapa colony was in full blood production, while an A. panamaen
sis colony was in the last stage of colony decline, and a nearby A. panamae
nsis colony had terminated only weeks before. The appearance of a small agg
regation of A. panamaensis in a montane cloud forest site, too small to sup
port a colony. as large as those that had recently reached the end of a col
ony cycle in a nearby premontane gallery forest, suggests that the colony c
ycle of A. panamaensis in northwestern Costa Rica Iras a seasonal pattern t
hat includes elevational migration and possible non-nesting quiescence at c
ool high elevations. Morphometric contrasts of queen and worker A. yepocapa
confirm caste dimorphism that hus been reported for other Agelaia species.
The multivariate analysis presented here reveals caste differences that ca
rr only have occurred as a result of a dichotomy in developmental pathways
during larval growth. Individuals of both species performed the behavior of
gaster flagging during colony defense. The role of gaster flagging in thes
e wasps is unknown. Near-nest aggressiveness of cavity-nesting wasps is hig
her than that of wasps that nest in exposed locations, perhaps as a correla
te of the scarcity of suitable cavities for nesting. The sting of A. panama
ensis is particularly painful. The A. panamaensis colony that was in declin
e was host to diverse inquilines and a parasitoid. The A. yepocapa nest col
lection included two parasitoid species.