Tegeticula intermedia (Riley)

Adult Characteristics

Wing expanse 18-29 mm. Forewing wide and blunt, usually white but occasionally with more or less tan coloration in northeastern part of range. Hindwing medium to light brownish grey, darkest by apex, gradually turning white toward hind corner; generally lighter in southernmost populations. Female with vestigial maxillary tentacles. Male genitalia with aedeagus 1.3-1.5 mm long, 0.07-0.08 mm in cross section; female genitalia with posterior apophyses 4.6-5.3 mm long, corpus bursae with signa 1.20-1.30 mm in diameter.

Comparison with Similar Species

Similar to many species in the yuccasella complex, especially the largely sympatric yuccasella and cassandra, but females lack functional maxillary tentacles in this non-pollinating cheater species. Specimens with tan coloration are also assignable to intermedia. Genitalic characters are also helpful in obtaining a definitive identification. A diagnostic key is provided.

Host, Oviposition, and Larval Feeding Habits

The species is known from the capsular-fruited yuccas Yucca filamentosa (Y. smalliana, Y. flaccida), Y. glauca (Y. arkansana, Y. campestris), Y. constricta, and Y. baileyi var. intermedia.. Females oviposit into young fruit (Pellmyr 1999). Eggs are laid very superficially under the fruit surface, and the larva feeds on developing seeds. Pupation occurs in a cocoon in the soil.

Geographic Distribution

Throughout the Great Plains and areas east of it, extending into central New Mexico.

Habitat

Natural habitats include sand dunes, pine forest and glades in the east, and grassland, shrub desert, and pinyon forest elsewhere. Altitudinal range 0 - 1400 m.

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Grassy shrub in Comanche Co., Texas, and a cleared area in Lowndes Co., Mississippi, represent typical habitats of host yuccas.

Type

Lectotype in MCZ.

References

Pellmyr, O. 1999. Systematic revision of the Tegeticula yuccasella complex (Lepidoptera: Prodoxidae) north of Mexico. Systematic Entomology 24:243-271.