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Ve1vetbean Caterpillar:! A Rearing Procedure and Artificial Medium
2
,a
G. L. GREENE:
N. C.
LEPPLA,·
and W. A.
DICKERSON"
ABSTRACT
Rearing procedures and a semisynthetic diet are pre-
sented for culturing Anticarsia gemmatalis Hiibner. In-
sects reared on the prepared diet wcre comparable to
those reared on soybean leaves except for a slight in-
crease in generation time and larval mortality.
visioned cups were incubated at 28±2°C and 65±5%
RH. Wax coated 354-ml squat paper cups contain-
ing 177-236 ml of diet yielded 25-30 pupae/cup.
while 30 ml plastic cups yielded 3-6 pupae/cup.
Pupae were collected 3 days after pupation and sur-
face sterilized using the techniques described for the
eggs. The pupae were then dried and returned to
the Plexiglas cages for emergence and oviposition.
Diet Preparation and Evaluation.-Several diets in-
cluding the pinto bean (Shorey and Hale 1965) and
the wheatgerm (Vanderzant 1967) were evaluated
and modified. A diet combination containing pinto
beans, wheat germ. and soybean protein proved to
be equal or superior to others. The following formula
makes ca. 4 liters of this medium:
Combine ingredients 1 and 2 at room temperature
in a 4-liter pyrex beaker and mix thoroughly.
Sequentially add ingredients 3-7 while heating the
solution to 75°C. Continue mixing while the tem-
perature cools to 68°C. Add ingredients 8-13, blend
at high speed for one minute and pour into rearing
containers.
The nutritional adequacy of the diet was compared
to soybean leaves by appraising larval development,
mortality, and fecundity of subsequent adults. Larvae
reared on soybean leaves were placed individually in
a 60 ml plastic cup, with fresh soybean leaves added
daily. Those reared on the semisynthetic diet were
placed in 30-ml plastic cups containing ca. 12 ml of
medium.
RESULTSAND DISCUSSION.-Oviposition cages were
initially provided with Gro-Iux lighting, and females
laid an avg. 32 eggs each under these conditions.
Cool white fluorescent and incandescent lights were
added in the oviposition area and the eggs per fe-
male increased to 189. As with most other Lepidop-
Laboratory rearing of the velvetbean caterpillar,
Anticar.lia gemmatalis Hubner, has facilitated bio-
logical studies in Florida and Missouri on this soy-
bean pest. Previously, only natural field populations
or laboratory colonies sustained on soybean leaves
were available for research. Larvae obtained this way
were often variable in size and frequently infected
with a fungus, Nomuraea rileyi (Farlow), as well as
with other pathogens common in Florida soybean
fields (Watson 1916, Allen et aL 1971). In an effort
to provide dependable laboratory populations, sev-
eral larval diets used for other Lepidoptera were
evaluated and modified. The semisynthetic diet and
rearing techniques persented here have been used to
continuously rear a sizable colony of velvetbean
caterpillars for over 40 generations.
METHODSANDMATERIALS.-Culturing Technique.l.-
Velvetbean caterpillar colonies were established by
using larvae collected from soybeans and adults re-
moved from BL traps in Florida and Missouri. Larvae
were fed soyeban leaves until pupation. Upon emerg-
ing, these adults as well as those from BL traps were
placed in 30X30X45 em Plexiglas® cages. The cages
were maintained at 28±2°C and 90±5% RH with a
14-16 h photoperiod using incandescent, cool white,
and Gro-Iux® lamps for lighting. A low intensity
(5w) incandescent light remained on during the
scotophase. A section of wet-strength paper towel was
taped flat against one side of the cage to serve as
oviposition substrate. Moths were provided daily a
feeding solution of I g honey, 0.1 g ascorbic acid,
0.1 g methyl para-hydroxybenzoate, and 6 g sucrose/
100 ml water saturated in pads in 60 ml paper cups.
The egg laden paper towel was exchanged daily
with a fresh towel. Eggs were either allowed to hatch
on the towel or surface sterilized and removed from
paper towel by immersing in a 0.25% solution of
sodium hypochlorite for 5 min. The eggs were then
washed for 5 min in demineralized water, neutralized
for 2 min in a 10% sodium thiosulfate solution,
transferred to fresh demineralized water, collected in
an eye dropper and dispensed on sterile paper towel
glued to the inside lids of the rearing container
(Leppla et al. 1974). After infestation, the pro-
1
Lepidoptera: Noctuidae.
"Fl. A!(ric. Exp. Stn. J. Ser. No. 7007. Received for publication
Nov. 3. 1975.
3
Mention of a commercial or proprietary product in this paper
does not imply endorsement of that product by the USDA.
• Vni•. of Florida, A!(ric. Res. Ctr., Quincy. FL 32351.
" Insect Attractants, Behavior and Basic Biology Research, Agric.
Res. Serv.. USDA. Gainesville, FL 32601.
o
Biological Control of Insects Research. Agric. Res. Serv., USDA,
Columbia. MO 65201.
Ingredients
1. Water
2. Gelcarin®/HWG
3. Pinto beans (dry)
4. Wheat germ
5. Soybean protein
6. Casein
7. Torula yeast
8. Ascorbic acid
9. Vitamin mixture (Vanderzants NBC)
10. Tetracycline
II. Formalin (40%)
12. Methyl P-hydroxybenzoate
13. Sorbic acid
Quantity
3400 ml
46g
250g
200g
100g
75
g
125g
12
g
20g
250mg
12ml
109
6g
487
488
GREENE ET AL.: REARING VELVETBEAN CATERPILLAR
Vol. 69, no. 4
Table I.-Comparison of semisynthetic diet to soybean
leaves as larval food for velvetbean caterpillar.-
Avg.
%
%
days Avg.
adult
pupat-
to pu-
pupal
emer- Eggsj
Diet ing pation vito gence
~
Semisynthetic
79 15.5
221
95
189
Soybean leaf 89 13.4
227
95
176
- All values are based on ca. 200 individuals reared on each diet.
tera, the velvetbean caterpillar requires high humid-
ity and moderate temperatures (80-90%
RH
and
25-30'C) for optimum oviposition.
At least 8 different existing diets for lepidopteran
larvae were evaluated in preliminary attempts to rear
velvetbean caterpillars in Florida and Missouri, but
these formulations failed to produce viable colonies.
Initially, Ist-3rd instars did not establish on pinto
bean or wheat germ media; however, addition of
casein and soybean protein promoted feeding by
young larvae and produced viable adults. In the
absence of soybean protein, more than 50% of the
neonate larvae failed to molt. After incorporation
of this major and other minor refinements, the
modified pinto bean-wheat germ diet and the rearing
techniques presented here were used to produce over
40 continuous generations with no apparent reduc-
tion in viability. Comparisons between this refined
diet and soybean plants as larval food were conducted
from the 4th-10th generation (Table 1) _ A ca. 15%
increase in generation time and a slight increase in
larval mortality were the only disadvantages associ-
ated with this diet, and these differences were not
significant at the 5% level.
REFERENCES CITED
AIlen, G. E., G. L. Greene, and W. H. Whitcomb. 1971.
An epizootic of Spicaria rileyi on the velvetbean
caterpillar, Anticarsia gemmatalis, in Florida. Fla.
Entomol. 54: 189---91.
Leppla, N. C., S. L. Carlyle, and T. C. Carlysle. 1974.
Effects of surface sterilization and automatic collec-
lion on cabbage looper eggs.
J.
Econ. Entomol. 67:
33-6.
Shorey, H. H., and R. L. Hale. 1965. Mass-rearing of
the larvae of nine noctuid species on a simple arti·
ficial medium. Ibid. 58: 522-4.
Vanderzant, E. S. 1967. Wheat-germ diets for insects:
rearing the boll weevil and the salt-marsh caterpillar.
Ann. Entomol. Soc. Am. 60: 1062-6.
Watson,
J.
R. 1916. Control of the velvetbean cater-
pillar. Fla. Agric. Exp. Stn. Bull. 130: 45-58.
