= eesr.”6hOhCtCO 
THE OVIPOSITION RESPONSE OF INSECTS 13 
throws considerable light upon it.? Craighead finds that nearly all 
adult cerambycids display a marked preference for the host wood 
in which they have fed as larvee, and that certain species which can 
be induced to feed in a new host show a preference for that host 
when they become adults. Concerning oviposition, he says (14. p. 
220) : ‘ iriwdy 
Although the’ adults show a decided predilection for a favored host in 
ovipositing and even, in certain species, a preference for the plants in which 
the larve have fed for one or two generations, the. instinct to oviposit seems 
to overbalance that of host selection, consequently new hosts are frequently 
selected—possibly more frequently in nature than is generally realized. 
If it can be shown that the food of the larva determines the host 
preference of the adult, a decided step in advance will have been 
made. Another step then will be to explain whether the “ memory ” 
of the food plant which the larva has passed on to the adult is the 
result of or is influenced by the chemical or physical effects of 
the food in the growing larva. 
CONCLUSIONS 
ne following internal factors may condition the oviposition 
responses of insects: The nutritive state as affected by the amount 
and chemical constitution of the food, age, fertility, and internal 
stimuli which determine periodic egg-laying. 
The external influences which may affect the oviposition response 
are temperature, humidity, hght (including color), air currents (and 
probably in some species water currents), the physical character of 
surfaces, the chemical constitution of substances which stimulate on 
contact, and the volatile constituents of substances. 
The simplest oviposition responses are probably shown by insects 
which spend most of their lives wpon substances that serve as food 
for themselves and their offspring. 
Most. free-living insects, however, require a chain of stimuli to 
provoke egg laying; a single stimulus is insufficient to call forth a 
normal response. Many species demand a specific chain of stimuli. 
The odor of a substance may attract gravid female insects, but is 
probably never in itself sufficient to induce normal oviposition. 
. LITERATURE CITED 
(1) ApotepH, Epwarp F. 
1920. Egg-laying reactions in the pomace fly, Drosophila. Jn Jour. Expt. 
Zool., vol. 31, pp. 327-041. 
{2) BACHMETJEW, P. 
1907. Experimentelle entomologische Studien. vol. 2, xvi+944+cviii 
pp., 31 figs., Sophia. 
(3) Back, E. A., and PEMBERTON, C. E. 
1914. Life history of the melon fly. Jn Jour. Agr. Research, vol. 3, 
pp. 269-274. 
(4) BAILLoN, P. CAPPE DE. 
1920. Contribution anatomique et physiologique 4 l’etude de la repro- 
duction chez les locustiens et les grilloniens, I. La ponte et 
Véclosion chez les locustiens. Jn La Cellule, vol. 31, pp. 1-245. 
(5) Barrows, WILLIAM MorrTon. 
1907. The reactions of the pomace fly, Drosophila ampelophila Loew, to 
odorous substances. Jn Jour. Expt. Zool., vol. 4, pp. 515-537. 
2 Ci re ro 
7 An important discussion by Brues of this and similar cases has recently appeared (cf. 
Amer. Nat., vol. 58, pp. 127-144, 1924). 
