The text below is grayed out because it is not intended to be read. It is a necessarily imperfect OCR of the original and is only used by a search engine.
1961
Journal of the Lepidopterists9 Society
23
PALATABILITY OF NORTH AMERICAN MODEL AND MIMIC BUTTERFLIES TO CAGED MICE
by Jane Van Zandt Brower and Lincoln P. Brower
During August and September of 1954, preliminary experiments were conducted to investigate the palatability of model and mimic butterflies to individually caged Feromyscus leucopus (Rafinesque), a deer mouse. This work was carried out in the Great Smoky Mountains of Tennessee and North Carolina, where the presumably unpalatable Battus philenor (Linne) and some of its supposed mimics were relatively abundant. Among the butterflies tested were: B. philenor, model; Papilio troilus Linne and Limenitis astyanax (Fabricius), mimics; and the male of P. glaucus Linne, the male of Speyeria diana (Cramer), S. aphrodite (Fabricius), and S. cybele (Fabricius), here called non-mimetic butterflies (i. e., butterflies which are not involved in mimicry, either as models or mimics).
The Feromyscus were obtained by trapping in the Great Smoky Mountains at an altitude of about 4,500 feet. The laboratory diet of the mice consisted of sunflower seeds, nut meats, and lettuce.
All of the butterflies were caught daily as adults along North Carolina route 284 between Dellwood and Mount Sterling, or along the Davidson River road in Pisgah National Forest. Both male and female butterflies were used, unless otherwise noted.
For each experiment from five to nine living, fluttering butterflies were placed in each mouse cage at about 11:00 p.m. The proportions of models, mimics, and non-mimetic butterflies varied from one experiment to another. The butterflies were left overnight in the mouse cages, and the remains were recorded the following day according to three categories : (1) left — if a butterfly was intact and alive, or dead but not bitten; (2) killed — if a butterfly was killed by a mouse, but not eaten; (3) eaten — if all that remained of a butterfly were wings and legs. The data for each butterfly species given to two mice are on Tables 1 and 2.
Other data were not comparable because there was more than one mouse per cage; however, the records show that 9 B. philenor, 3 P. troilus, and 8 non-mimetic butterflies were eaten, and none left or merely killed, in a cage of an adult male and a juvenile P. leucopus.
These limited findings suggest that P. leucopus feeds rather indis-criminantly upon butterflies; the presumed unpalatability of B. philenor was not borne out in these tests, although the results show some indication that B. philenor was less palatable to Mouse No. 2 than the other
24
Brower & Brower: caged mice
Vol.15: no.l
|
Table 1. REACTION OF MOUSE |
NO. 1 TO |
BUTTERFLIES. |
|
|
Butterfly Species Left |
Killed |
Eaten |
Total |
|
B. philenor 0 |
0 |
17 |
17 |
|
P. troilus 0 |
0 |
6 |
6 |
|
L. astyanax 0 |
0 |
2 |
2 |
|
S. diana (male) 0 |
0 |
3 |
3 |
|
S. aphrodite 0 |
0 |
2 |
2 |
|
S. cyhele 0 |
0 |
3 |
3 |
|
P. glaucus (male) 0 |
0 |
2 |
2 |
|
Table 2. REACTION OF MOUSE |
NO. 2 TO |
BUTTERFLIES. |
|
|
Butterfly Species Left |
Killed |
Eaten |
Total |
|
B. philenor 3 |
1 |
10 |
14 |
|
P. troilus 0 |
0 |
6 |
6 |
|
L. astyanax 0 |
0 |
2 |
2 |
|
S. diana (male) 0 |
0 |
5 |
5 |
|
S. aphrodite 0 |
0 |
1 |
1 |
|
S. cyhele 0 |
0 |
4 |
4 |
|
P. glaucus (male) 0 |
0 |
1 |
1 |
butterflies were. That mimicry is effective in the B. philenor complex was demonstrated subsequently with Florida Scrub Jays, Cyanocitta ccerulescens ccerulescens (Bosc), as caged predators (Brower, 1958).
Merriam (1893) and Webster (1902) noted that mice (Onychomys) have been reported to eat the presumably distasteful Danaus plexippus (Linne), the Monarch, which overwintered on an island in Aransas Bay off the coast of Texas. In September 1954, in New Jersey, we obtained some experimental evidence that D. plexippus is also palatable to P. leucopus. The same four mice ate a total of 18 adults, 14 full grown larvae, and 3 pupae of D. plexippus, whereas none were left or only killed.
Although mice have seldom been considered as possible predators of butterflies, the evidence presented here indicates that P. leucopus will eat them. However, the nocturnal habits of mice and their correlated lack of color vision would seem to make their participation as selective agents in mimicry unlikely.
This work was supported by a Sigma Xi RES A Grant and the Higgins Fund of Yale University.
References
Brower, J. VZ., 1958. Experimental studies of mimicry in some North American butterflies. Part II. Battus philenor and Papilio troilus, P. polyxenes, and P. glaucus. Evolution 12: 123-136.
Merriam, C. H., 1893. Danais archippus eaten by mice. Insect life 5: 270.
Webster, F. M., 1902. Mice destroying insects. Ent. news 13: 277-280.
Department of Biology, Amherst College, Amherst, Mass., U. S. A.