WEST INDIAN MELOIDAE — SELANDER AND BOUSEMAN 201 



Indies have always been separated from the American mainland by a 

 barrier so formidable to Meloidae that phoresy has been a prerequisite 

 to successfid colonization of the islands. That only a few of the 

 phoretic meloid species have established themselves in the West 

 Indies does not detract from our hypothesis. 



Phoresy as a means of dispersal seems to confer two principal ad- 

 vantages on the meloids possessing it. First, by attaching themselves 

 to adult bees, meloid larvae are able to take advantage of the powers 

 of flight of their host, which in general are considerably greater than 

 those of adult meloids. This advantage increases a meloid species' 

 chances of crossing a physical barrier such as an extensive water gap 

 and of reaching a suitable habitat. Second, since many meloid larvae 

 frequently attach themselves to individual adult bees, a bee reaching 

 and establishing itself in a new area may introduce several meloid 

 individuals and thus considerably enhance the prospect of the 

 species' success, particularly since the larvae attached to a single bee 

 will develop and emerge as adults in the same locality. 



The hypothesis that phoresy is an important factor in the dispersal 

 of the Meloidae gains support from the fact that the West Indian 

 meloid fauna is composed of two distinct groups. These, on the 

 basis of phylogenetic studies pursued by the senior author (Selander), 

 seem to have developed phoresy independently. Tetraonyx, Cissites, 

 Pseudozonitis, and Nemognatha constitute one group (the subfamily 

 Nemognathinae) and share a number of specialized characters besides 

 phoresy. Meloe, on the other hand, closely resembles the nonphoretic 

 Meloidae (which we place with it in the subfamily Meloinae) except 

 in those features directly connected with phoresy. Indeed, we may 

 say that the only distinctive similarity between Meloe and the rest 

 of the genera represented in the West Indies that is conceivably 

 critical in dispersal is phoresy. 



Acknowledgments 



We wish to acknowledge with gratitude the generous assistance of 

 the following individuals and institutions in providing us with the 

 material and information upon which this report is based: Patricia 

 Vaurie, American Museum of Natural History (AMNH); Christine 

 M. F. von Hayek, British Museum (Natural History) (BM); 

 R. Benard, Institut National de la Recherche Agronomique, Centre 

 de Recherches Agronomiques des Antilles, Petit-Bourg, Guadeloupe 

 (INRA); Edward A. Chapin, Museum of Comparative Zoology 

 (MCZ); T. H. Farr, The Institute of Jamaica, Kingston (IJ); M. H. 

 Hatch, University of Washington (UW) ; L. F. Martorell, Agricultural 

 Experiment Station, University of Puerto Rico; J. R. Metcalfe, 

 Department of Science and Agriculture, Barbados; J. A. Ramos, 

 University of Puerto Rico (UPR); T. J. Spilman, U.S. National 



