Most Agathidines are solitary
koinobiont endoparasitoids of concealed
Lepidoptera larvae. However, the tribe
Disophrini attacks free living Lepidoptera larvae. The tribes
Agathidini and
Earinini attack the first and second
instar larvae of their hosts, contrasting with the Disophrini, which attack later instars, as well as the
Cremnoptini, which parasitize every larval stage. Most species are diurnal, but many Disophrini are
nocturnal, with pale coloration and enlarged
ocelli. Agathidines have three larval
instars. They likely seek out and kill competitors as first instars. As final instars, they emerge from their
host caterpillar, feed externally, then spin their
cocoons.
Temperate species
overwinter in their hosts during their first instar. Most tropical species are brightly colored and are involved in
mimicry. Studies of the species
Alabagrus texanus have found that males that arrive early to a site where females recently emerged from were often successful, but the very young and very old males were always unsuccessful. Males also had
short-term memory regarding sites of female emergence. Agathidines have been noted to be more abundant in ecosystems where fluids are harder to obtain. Many have concealed nectar extraction adaptations (CNEAs) that make them more adapted to gaining nectar from flowers, "perhaps particularly from
Asteraceae." These CNEAs include elongate malar regions, galea, glossa, and maxillary palps that form a tube. These elongate mouthparts have independently evolved in the subfamily six times. == Taxonomy and phylogeny ==