ON THE LIFE CYCLE AND NATURAL HISTORY OF 
HYMENITIS NERO (LEPIDOPTERA: ITHOMIINAE) 
IN COSTA RICA* 
By Allen M. Young 
Department of Biology, Lawrence University 
Appleton, Wisconsin 5491 1 
A knowledge of life cycle and natural history are often important 
prerequisites to studies of population biology in butterflies. Although 
studies on the systematics and broad distribution patterns of that 
familiar New World Tropical group, the Ithomiinae, have been 
conducted (Seitz, 1924; Fox, 1956; Fox, 1968), a lot remains to 
be known about the biology of many species in Central America. 
This is surprising in light of the considerable interest in these but- 
terflies as members of mimicry complexes. In this spirit, this paper 
summarizes life cycle and natural history data on a clear wing itho- 
miine Hymenitis nero (Hewitson) (Nymphalidae: Ithomiinae) in 
Costa Rica, Similar studies of several other sympatric ithomiines 
have either been completed (Young, in prep.) or begun, as a pre- 
liminary step towards understanding the local patterns of diversity 
of this family in selected tropical plant communities. 
Methods 
Field observations were conducted during July and August 1971, 
and again during August 1972 at Cuesta Angel, a montane tropical 
wet forest locality (1000 m. elev.) on the Caribbean slope of the 
central Cordillera in the Heredia Province of Costa Rica. Here, the 
study site was at the bottom of a steep ravine (about 250 m. in 
depth) along the headwaters of the Rio Sarapiqui. Observations were 
confined to a small (20 X 25 m) second-growth clearing near 
heavily-shaded primary-growth forest canopy. 
Field studies consisted of: (1) observations of oviposition se- 
quences, (2) records of the larval host plant, (3) notes on larval 
behavior, and (4) notes on adult behavior and occurrence with 
other ithomiids. 
Laboratory studies dealt with the estimation of developmental 
time and description of the life cycle. For these studies, eggs, col- 
lected immediately after oviposition in the field, were brought into 
the laboratory (San Jose, Costa Rica) and rearing studies were done 
in large clear plastic bags containing ample sprigs of host plant. 
* Manuscript received, by the editor October 5, 1972 
284 
