yuccasella complex

T. yuccasella (Riley) complex

N.B.: Tegeticula yuccasella is a large complex containing many undescribed species. The present entry is a composite, and a modified entry will appear here after description.

Adult Characteristics

Wing expanse 13-33 mm. Forewing white, with hindwings ranging from white to dark gray.

Comparison with similar species

Some members of the complex can be mistaken for white individuals of Prodoxus quinquepunctellus. The latter is of more tenuous build, and is often far smaller. The valvae of male quinquepunctellus constitute a larger proportion of the abdomen (up to one third of its length) and they rise like a bow above the remainder of it. The valvae also have 5-10 blunt spines along the outer edge, which are replaced by a pollex in yuccasella. The ovipositor of yuccasella females is much finer, and not visibly serrated under low magnification, whereas quinquepunctellus has a thick, dark ovipositor with distinct dorsal serration.

Hosts, oviposition, and larval feeding habits

Members of the complex feed on seeds of different species of fleshy-fruited and capsular-fruited Yucca (Agavaceae), with host specificity ranging from monophagy to oligophagy (Pellmyr et al 1996). Females oviposit into flowers, or, in the case of cheaters, into developing fruit (Addicott 1996, Pellmyr 1996). The larva feeds on developing seeds. Pupation occurs in a cocoon in the soil.

Female member of the complex actively pollinating a Y. filamentosa flower.

Larva of a yuccasella complex species after emergence from the pod, ready for diapause.

Geographic distribution

The range of the yuccasella complex is coincident with that of the genus.

Habitat

In desert, grassland, oak-pine woodland, or coastal chaparral, clearings, and dunes with Yucca.

Shrubby deserts in Brewster Co., Texas, and Dona Ana Co., New Mexico, grassy shrubland in Comanche Co., Texas, and a cleared area in Lowndes Co., Mississippi, represent typical habitats of host yuccas.

A phylogenetic-ecological note

As indicated in the genus note, a wide variety of evolutionary and ecological studies have been performed using members of this group, but incomplete systematics make such work a perilous proposition. Cheaters were first recognized in 1881 (Riley 1881) and several students have suggested that multiple species are compiled under the yuccasella label (e.g., Busck 1947, Davis 1967, Miles 1983, Addicott 1986), but a modern treatment is wanting. Given the fame of the group, it may surprise some that there is a dearth of specimens with good biological information, which has held back progress. A formal revision of the complex is now in progress (Pellmyr et al 1996). Stay posted.

References

Addicott, J.F. 1986. Variation in the costs and benefits of mutualism:
          the interaction between yuccas and yucca moths. Oecologia 
          70:486-494
Busck, A. 1947. Family Prodoxidae. In McKelvey, S.D. 1947. Yuccas of 
          the southwestern United States, pt. 2.  Pp. 180-185.
Davis, D.R. 1967. A revision of the moths of the subfamily  Prodoxinae 
          (Lepidoptera: Incurvariidae). U.S. Nat. Hist. Mus., 
          Bull.  255:1-170.
Miles, N.J. 1983. Variation and host specificity in the yucca moth, 
          Tegeticula yuccasella (Incurvariidae): a morphometric approach.
          J. Lep. Soc. 37:207-216
Pellmyr, O., J. Leebens-Mack & C.J. Huth. 1996a. Non-mutualistic 
          yucca moths and their evolutionary consequences. Nature 
          380:155-156.
Riley, C.V. 1881. Further notes on the pollination of Yucca and on 
          Pronuba and Prodoxus. Proc. Amer. Acad. Assoc. Adv. Sci. 
          29:617-639.

Lectotype in USNM.

About this page

Olle Pellmyr
E-mail: pellmyr@ctrvax.vanderbilt.edu.
Dept of Biology, Vanderbilt University, Box 1812-B Nashville, TN 37235, USA

Title illustration: Members of the yuccasella complex.