U.S. Department of Agriculture

Forest Seruice Research Note S E - 295

May 1980

DURATION OF THE LARVAL, PUPAL, AND MOTH STAGES OF

THE SOUTHERN PINE CONEWORM

DIORYCTRIA AMATELLA (HULST)’

by Isadore L. Williams and Carl W. Fatzinger’

ABSTRACT.-The day’s duration of each developmental stage of the southern pine coneworm,

Dioryctriu umareh (Hulst), when reared on artificial medium was determined under controlled

laboratory conditions. These results will provide a method for estimating the availability of the

different stages during rearings without the necessity of measuring larval-head capsule widths or

closely observing colonies for evidence of larval ecdysis, pupation, or moth emergence.

Keywords: Duration, head capsule, life stage, pupation.

The southern pine coneworm, Dioryctvia

amatella (Hulst), is one of the most destructive

insect pests in pine seed orchards of the Southeastern United States. Larval feeding on the

flowers, conelets, cones, and shoots of southern

pines can reduce yields of pine cones by as much

as 35 percent. The life history of D. amatella has

been reported in part by Ebel (1963, 1965),

Neunzig and others (19&l), Coulson and Franklin

(1970), and Ebel and others (1975).

When reared on artificial medium at 27” C

under a die1 photoperiod of 12 h light: 12 h darkness, the average day’s duration for stages of D.

amatella was: egg, 5.4 days; larval, 27.8 days;

pupal, 14.5 days: and moth, 11.4 days with a total

generation time” of 47.9 days.4 The duration of

each of the five larval stages (Fatzinger 1970) has

not been reported.

In this study, we determined the day’s dura-

‘Lepidoptera: Pyralidae (Phycitinae).

“Williams and Fatzinger are Research Entomologists,

Naval Stores and Timber Production Laboratory, Olustee,

Florida.

“Generation time was calculated as the average of the

durations of larval and pupal stages for female insects plus the

average number of days from female moth emergence to egg

deposition and egg hatch.

“Fatzinger, C. W. A method for rearing the southern pine

coneworm on artificial medium, with observations on mating

behavior. (In preparation.)

tion of each of the larval stages when reared on

artificial medium as well as the day’s duration of

the pupal and adult stages. This information will

be useful for studies requiring insects of a given

stage of development.

METHODS

Eggs of D. amatella were obt.ained from the

39th succeSsive generation of a laboratory colony

reared on the AUTOWG+S medium (see footnote 4) at Olustee, Florida. First-stage larvae

(.Iones 1978), collected on the day they hatched

from eggs, were reared individually under a die1

photoperiod of 12 h light: 12 h darkness at 27°C on

the AUTOWG+S medium in 29.6 ml plastic condiment cups fitted with snap-on lids. Daily observations were made and the duration of each stage

of development was recorded. The appearance of

a moulted larval-head capsule was used as evidence of a change in larval stage. To avoid

damage to the tender newly formed pupae, they

were left in the larval-rearing containers from 2 to

3 days until they changed color from an initial

greenish white to a dark tan (Fatzinger and Asher

1971). The tan-colored pupae were transferred to

individual 59.2 ml plastic cups equipped with

snap-on lids and a small piece of sponge (about

1 x 1 x I cm) that was moistened daily with water

to maintain humidity. Upon emergence, moths

Southeastern Forest Experiment Station - Asheuille, North Carolina
were transferred to 4.7-liter jars fitted with wire different for males and females during larval

screen tops. They were provided with a S-percent stages I. IV. V. and for pupae (table 2). In general.

sucrose-water solution for feeding from a small mean duration of stages for females was slightly

sponge moistened daily in each jar. longer than that for males. The total time from

average egg hatch to average moth death was also

RESUL,TS AND DISCLJSSION significantly different (P < 0.01) between males

(49.5 days) and females (5 1.4 days).

Our observations on larval ecdyses during The numerical differences observed between

rearings confirmed Fatzinger’s (1970) findings sexes for duration of the first three larval stages

that D. umutella has tive larval stages. The first ranged from 0.03 to 0.07 days and increased from

four larval stages were about equal in duration 0.20 days for stage IV larvae to 0.88 days for stage

(table 1) with an overall average duration of 3.7 V larvae. The total difference of 1.9 days between

Table I.-Duration of the larval, pupal, and moth stages of D. amutelfu reared on an artificial medium

at 27” C

Developmental

stage

Insects

observed

(No.)

Duration of stages

Mean’ Range

(days)

Cumulative duration of stages

Mean”

(days)

I 800 3.98 ‘-c 0.02 2-7 3.98 2 0.02

II 724 3.26 k 0.04 2-7 7.26 ? 0.04

III 630 3.91 k 0.03 2-9 11.11 +- 0.05

IV 586 3.51 k 0.08 3-14 14.59 + 0.10

V 485 9.14 “_ 0.25 3-22 23.70 k 0.26

Pupa 427 15.30 k 0.21 5-27 38.94 r+ 0.3 1

Moth 408 11.58 2 0.46 1-28 50.52 2 0.53

days each. The duration of larval stage V, however, was at least 2.3 times longer than any of the

previous stages. This increased duration was

probably attributable to the additional time required after the larva ceased active feeding to

construct the pupal cocoon and for the pharate

pupal instar to form before pupal ecdysis. Total

duration of the larval stage was about 4 days

shorter than that observed by Fatzinger (see footnote 4) for D. amatella reared under the same

laboratory conditions. The duration of the pupal

stage was about 1 day longer, and duration of the

moth stage was about equal to that found by

Fatzinger.

The mean duration of stages was significantly

sexes for average colony duration from egg hatch

to moth death was only 3.8 percent of the average

colony duration for both sexes combined. The

differences in durations of stages between colonies reared, i.e., those reported by Fatzinger

(see footnote 4) and those reported here. are also

small. Thus, the average duration of stages listed

in table 1 should provide accurate estimates of the

stage of development of D. amatella when reared

as described above. These data provide a means

for estimating the availability of the different

stages in rearings without the necessity of

measuring larval-head capsule width or closely

observing colonies for evidence of larval ecdyses.

pupation, or moth emergence.
Table 2.-Comparison of duration of stages for male and female D. am&e/la reared on an artificial medium at 27” C

Developmental

stage

Insects

observed

(No.)

Duration of stages

Mean’ Range

(days)

Insects

observed

(No.)

Duration of stages

Mean’ Range

(days)

Significant

difference’

MALE FEMALE

I 226 3.98 + 0.02 2-4 254 4.01 2 0.02 4-6 *

II 226 3.19 2 0.06 3-6 253 3.16 + 0.05 3-5

III 226 3.87 t 0.04 3-4 253 3.94 ? 0.06 2-9

IV 224 3.39 ?Z 0.09 3-6 254 3.59 2 0.15 3-14 *

V 223 8.68 t 0.37 3-22 254 9.56 -c 0.33 5-19 **

Pupa 196 15.07 ? 0.29 8-20 228 15.56 -e 0.29 5-27 *

Moth 186 11.31 * 0.66 2-23 219 11.79 t 0.64 1-28

-

‘A t-test was used to test the differences between means[* = PI 0.05, ** = P < 0.01).

LITERATURE CITED Fatzinger, C. W.

Coulson. R. N., and R. T. Franklin.

1970. The biology of Dioryycrria amurella (Lepidoptera:

Phycitidae). Can. Entomol. 102:679684.

Ebel, B. H.

1970. The number of instars of Dioryctriu umafe//a

(Hulst) in north Florida. USDA For. Serv., Res.

Note SE-142. 3 p. Southeast. For. Exp. Stn..

Asheville, N.C.

1963. Insects affecting seed production of slash and

longleaf pines: Their identification and biological

annotation. USDA For. Serv.. Res. Pap. SE-6. 24

p. Southeast. For. Exp. Stn., Asheville, N.C.

Ebel, B. H.

Fatzinger, C. W., and W. C. Asher.

1971. Observations on the pupation and emergence behavior of Diorycrria abietellu (Lepidoptera:

Pyralidae (Phycitinae)). Ann. Entomol. Sot. Am.

64:413-418.

Jones, L. C.

1965. The Dioryctria coneworms of north Florida pines

(Lepidoptera: Phycitidae). Ann. Entomol. Sot.

Am. 58:623630.

Ebel, B. H., T. H. Flavell, L. E. Drake, H. 0. Yates III. and

G. L. DeBarr.

1975. Seed and cone insects of southern pines. USDA

For. Serv., Gen. Tech. Rep. SE-8, 40 p. Southeast. For. Exp. Stn., Asheville, N.C.. and Southeast. Area, State and Priv. For.. Atlanta, Ga.

1978. A note on the use of the terms instar and stage.

Bull. Entomol. Sot. Am. 71:491492.

Neunzig, H. H., E. D. Cashatt, and G. A. Matuza.

1964. Observation on the biology of four species of

Dioryctriu in North Carolina (Lepidoptera:

Phycitidae). Ann. Entomol. Sot. Am. 57:3 17-321.
The Forest Service, U.S. Department of Agriculture, is dedicated to the principle of multiple

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*U.S. IXVERNMENT PRINTING OFFICE: 1980-640-19014541. Region 4