Suitability of a non-host Palo Verde for development of Stator limbatus (Horn) (Coleoptera; Bruchidae) larvae

In the southwestern United States, there are five species of palo verdes (Cercidium and Parkinsonia sp.; Fabaceae). Stator limbatus (Horn), a seed beetle, has been reared from four of these: Cercidium floridum (Benth.), C. microphyllum (Torr.) Rose & Johnst., Parkinsonia aculeata Linnaeus, and P. macra. (Johnst.). However, despite extensive collections in North and Central America, S. limbatus has never been reared from P. texana (A. Gray) S. Watson. We tested the suitability of P. texana as a host for a Texas population of S. limbatus. Survivorship of S. limbatus on P. texana was high relative to the other palo verde species (except for C. microphyllum, on which survivorship was also high). Development time and body weight of emerging adults on P. texana were each approximately intermediate between those on C. floridum and P. aculeata (on which beetles developed slowly and emerged small) and C. microphyllum (on which beetles developed rapidly and became large adults). These data indicate that P. texana is a suitable host for S. limbatus and that, relative to other species of palo verde (except C. microphyllum), P. texana is a high-quality host. However, our study examines only the suitability of these palo verdes as hosts for S. limbatus in a controlled laboratory experiment. We discuss other hypotheses that may explain why P. texana is not used by S. limbatus in nature.