Biology ETDs

Publication Date

11-30-1972

Abstract

Life history studies of Rhyacionia neomexicana (Dyar) were conducted in 1969-71 on the Dudley Burn, Chevelon Ranger District, Sitgreaves National Forest, Arizona. This univoltine species overwinters as pupae in cocoons attached to the root collars of Pinus ponderosa Laws. seedlings. Peak adult emergence occurs in April and is protandrous. Males are lured to virgin females by a sex pheromone. Male flight activity occurs at 2000-2400 hr. Dissections for spermatophores indicate that females mate only once. Eggs are deposited singly or in overlapping rows on the inner surfaces of needles near the fascicles. Oviposition sites occur predominantly in the upper three whorls of foliage and on 1-year-old needles. Eclosion is completed by the end of June and developing larvae pass through five instars and three distinctive feeding stages: a cryptic needle mining stage before new shoots are attacked, a pitch tent stage when new needles on expanding shoots are severed and mined, and a shoot mining stage. Destructive feeding in upper crown terminal and lateral shoots causes height growth loss and a bushy growth form. Larvae leave the shoots in July and August and descend the tree boles for pupation below the soil. Hymenopterous parasitoids attack the eggs and dipterous and hymenopterous parasitoids emerge from infested shoots and host cocoons. Predators include ants, spiders, wireworms, birds, lizards, and mice.

Language

English

Document Type

Dissertation

Degree Name

Biology

Level of Degree

Doctoral

Department Name

UNM Biology Department

First Committee Member (Chair)

Clarence Clayton Hoff

Second Committee Member

Calvin L. Massey

Third Committee Member

Clifford Smeed Crawford

Fourth Committee Member

William Wayne Johnson

Fifth Committee Member

Loren David Potter

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