26 HARDWICK; Heliolonche life history Vol. 23, no. 1

THE LIFE HISTORY OF HELIOLONCHE CAROLUS (NOCTUIDAE)

D. F. HARDWICK Entomology Research Institute, Canada D epartment of Agriculture, Ottawa, Canada

H eliolonche carolus McDunnough 1 presents an anomaly among its relatives. Like the majority of in the H eliothidinae, H. carolus frequents the blossoms of its foodplant. Unlike its relatives, however, which are either inconspicuously marked and colored, or are protectively colored in their resemblance to the blossoms, H. carolus with its red and orange wings could not contrast more strongly with the white blossoms of its host, Hafinesquia neomexicana Gray. There are several possible explanations of the situation. may not be the sole foodplant of the species, and H. carolus may feed primarily on the head of another composite to which it bears a closer resemblance in color. Considering the strong host specificity of other such geographically restricted helio­ thidine moths, however, and the fact that there is evidently no closely related species with blossom coloring similar to that of H. carolus, within the known range of the insect, the theory is probably not a tenable one. A second explanation might be that was once a dichromatic or even polychromatic species, and that H. carolus became adapted to a dark red or orange blossom which the host species no longer has. A third possibility is that H. carolus evolved in association with a host plant now extinct, but before the extinction of the latter, managed to transfer to the possibly closely related Rafinesquia, to which it is not particularly well adapted, and on which its future existence may well be limited in time. The evident difficulty which the female moth has in ovipositing in the elongate head of Hafinesquia may lend some credence to the latter theory. Heliolonche carolus has been taken only at scattered localities on the Mojave D esert of southern , but its food plant is listed as ex­ tending from Inyo County southward through the Mojave and Colorado deserts to Mexico, and eastward to and . Specimens examined were taken on dates between the middle of March and the first week of May. The individuals from which eggs were obtained for life history studies, were captured in the spring of 1955 in the Whitewater Pass area at the southern margin of the Mojave. Although the species was not abundant

1 Heliolonche carolus McDunnough, 1936, Canad. Ent., 68: 45-46. 1969 Journal of the Lepidopterists' Society 27

in this area, copulation and oviposition were observed a sufficient number of times to preclude any misassociation of the moth and its food plant.

BEHAVIOR H eliolonche carolus is an exclusively diurnal species, and shares with other such day-flying noctuids a greatly reduced condition of the com­ pound eyes. Despite its evident conspicuousness to predators, H. carolus rests, feeds and copulates on the head of its food plant. During the process of copulation, the female commonly sits on top of the head while the male assumes a position on the side, below the ray petals. The female has a specialized oviposition pattern; in order to deposit its eggs near the base of the receptacle, the little moth laboriously burrows backward into the elongate head. 'When it has reached its maximum dcpth the crumpled wings of the insect are often left projecting above the surface of the blossom. The egg is usually inserted among the developing seeds, less frequently among the florets immediately above the seeds.

Figs. 1-3. Heliolonche carolus McDunnough. 1, Fifth stadium larvae, dorsal. 2, Fifth stadium larvae, left lateral. 3. Adult. Fig. 4. Rafinesquia neomexicana Gray, food plant