INSECTS OF HAWAII INSECTS OF HAWAII A Manual of the Insects of the Hawaiian Islands, including an Enumeration of the Species and Notes on Their Origin, Distribution, Hosts, Parasites, etc. VOLUME 17 HAWAIIAN HYLAEUS (NESOPROSOPIS) BEES (HYMENOPTERA: APOIDEA) by HOWELL V. DALY Professor Emeritus of Entomology University of California Berkeley, CA and KARL N. MAGNACCA Department of Entomology Cornell University Ithaca, NY University of Hawai‘i Press Honolulu CONTENTS ABSTRACT ................................................................................................................... 1 INTRODUCTION ........................................................................................................ 3 THE HAWAIIAN ISLANDS ............................................................................... 3 HISTORY OF COLLECTIONS AND TAXONOMY ........................................ 3 DISPERSAL AND EVOLUTION OF HYLAEUS SPECIES IN HAWAII ........ 7 BIOLOGY OF HYLAEUS ................................................................................... 9 NATIVE AND ADVENTIVE ENEMIES .......................................................... 9 ECOLOGY OF HYLAEUS IN HAWAII ........................................................... 11 NATIVE AND ADVENTIVE BEES OF THE HAWAIIAN ISLANDS .......... 12 DESCRIPTIVE TERMINOLOGY .......................................................................... 14 KEYS TO SPECIES................................................................................................... 24 KEY TO MALES.............................................................................................. 25 KEY TO FEMALES ......................................................................................... 34 TAXONOMY OF HYLAEUS (NESOPROSOPIS) SPECIES ................................ 43 NOMINA DUBIA ..................................................................................................... 209 ACKNOWLEDGMENTS ....................................................................................... 210 BIBLIOGRAPHY .................................................................................................... 211 APPENDIX: RECORDS OF RECENT COLLECTIONS................................... 217 INDEX ....................................................................................................................... 230 HYLAEUS SPECIES-GROUP NAMES ......................................................... 230 ARTHROPOD ENEMIES AND ASSOCIATES ............................................ 231 PLANTS USED AS NESTING SUBSTRATES ............................................ 231 FLOWER VISITATION RECORDS .............................................................. 231 HAWAIIAN HYLAEUS 1 ABSTRACT The native colletid bee species of the genus Hylaeus (Nesoprosopis) are revised for the Hawaiian Islands based on adult morphology. Sixty species are recognized. NEW SPECIES described by Magnacca and Daly are H. akoko and H. gliddenae from Hawaii; H. kukui and H. takumiae from Maui; H. kuakea, H. mana, H. mimicus, and H. nalo from Oahu; and H. kokeensis and H. solaris from Kauai. NEW SYNONYMIES are proposed (senior synonyms first): H. assimulans (Perkins) = H. assimulans oahuensis (Perkins); H. coniceps (Blackburn) = H. comes (Perkins); H. connectens (Perkins) = H. koae (Perkins), H. insulae Meade-Waldo (earlier replacement name for Nesoprosopis vicina Perkins), and Prosopis trigona Warncke (unwarranted replacement name for Nesoprosopis vicina Perkins); H. flavipes (F. Smith) = H. blackburni (F. Smith); H. fuscipennis (F. Smith) = H. fuscipennis obscuripes (Perkins), H. fuscipennis swezeyi (Cockerell), and H. caeruleipennis (Perkins); H. haleakalae (Perkins) = H. neglectus (Perkins); H. nivicola (Meade-Waldo) = Prosopis farinosa Warncke (unwarranted replacement name for Nesoprosopis nivalis Perkins); H. paradoxicus (Perkins) = H. erythrodemas (Perkins); H. rugulosus (Perkins) = Prosopis ovatula Warncke (unwarranted replacement name for Nesoprosopis rugulosa Perkins); H. specularis (Perkins) = H. homoeochromus (Perkins); H. unicus (Perkins) = H. binominatus Meade-Waldo (earlier replacement name for Nesoprosopis laticeps Perkins) and Prosopis avara Warncke (unwarranted replacement name for Nesoprosopis laticeps Perkins). NEW COMBINATIONS are Hylaeus muranus (Warncke) and Hylaeus niloticus (Warncke). The following names are considered nomina dubia: “Nesoprosopis rubrocaudatus Blackburn and Cameron” and “Nesoprosopis attripennis Perkins.” The history of collections of the bees, their taxonomy, attributes for dispersal, and their biology and ecology are discussed. Taxa of adventive bees are characterized as an aid to identification of native species. Terminology used in the treatment is explained, followed by keys to the identification of species based on adult males and females. Treatment of each species includes annotated synonymy and other references; diagnosis of identifying features and general distribution; description of male and female; localities where first collected and recent collections; flower records; remarks on taxonomic problems and other information; and line illustrations. Recent collection records are provided in an appendix. 2 INSECTS OF HAWAII VOL. 17 Fig. 1. Map of major islands in the Hawaiian Island chain (after Zimmerman 1948:10). HAWAIIAN HYLAEUS 3 INTRODUCTION The native bees of the Hawaiian Islands are believed to have evolved from a single lineage of the genus Hylaeus (family Colletidae) and are assigned to the subgenus Nesoprosopis. The genus Hylaeus is worldwide in distribution with 46 subgenera and an estimated 579 species (Michener 2000:62). The subgenus Nesoprosopis is among the largest of the subgenera with 60 of its species found in the Hawaiian Islands and eight species in the Oriental region. The latter includes one species also known from the Palearctic region (Hirashima 1977, Ikudome 1989). About three-quarters of the species described from the Hawaiian Islands by Perkins (1899, 1910, 1911) have been collected recently (Table 1). Some are still as rare or as abundant as he observed, yet others, formerly abundant, have not been collected recently. After more than a century, we have little knowledge of their mating and nesting habits, food preferences, natural enemies, or roles as pollinators of endemic Hawaiian plants. The purpose of this volume is to encourage future research by facilitating identification and by documenting the survival of these interesting bees. The Hawaiian Islands Hawaii consists of an east-west chain of volcanic islands, each formed as the Pacific plate moves over a stationary hot spot in the Earth’s crust. There are currently six high islands (Fig. 1), along with two smaller ones and a chain of subsided low islands and coral atolls stretching WNW to Midway. Beyond that, the Emperor Seamounts extend nearly to Kamchatka. Eruptive activity is almost entirely restricted to the youngest island, Hawaii, which is about 500,000 years old and still growing. The oldest high island at present, Kauai, is about 5.1 million years old, but it is believed that there has been at least one high island (i.e., one capable of inducing rainfall and thus supporting a diverse biota) continuously since Kure, about 29 million years (Carson and Clague 1995). As islands subside and erode, volcanoes that were previously joined by land bridges are separated by channels. The islands of Maui, Molokai, Lanai, and Kahoolawe (referred to collectively as Maui Nui) were once joined in this way; earlier, Molokai was probably joined to Oahu. However, Kauai was never linked to Oahu, nor Hawaii to Maui, although the channels were much narrower in the past. Because of Hawaii’s great isolation – the Islands are over 3500 km from any continental landmass, the most isolated high islands in the world – the flora and fauna are derived from relatively few introductions. As a result, they are depauperate at the family level, but contain a number of extraordinary radiations, such as the celebrated Drosophila flies, and the Clermontia and Cyanea lobelioids. Hylaeus may be included among these; there are more species of the genus in the Hawaiian Islands than the 48 species in America north of Mexico. History of Collections and Taxonomy The first specimens of bees from the Hawaiian Islands were collected during the voyage of the British ship Blossom commanded by Captain Frederick William Beechey. The specimens 4 INSECTS OF HAWAII VOL. 17 Table 1. Checklist and distribution of Hylaeus (Nesoprosopis) in the Hawaiian Islands. Key: | = original published Perkins’ records (1899, 1910, 1911) and Perkins’ collection, but not recently recollected; z = Perkins’ records and recently collected (after 1989); } = new records for islands (from recent collections unless noted); = new species. The last row provides the sum of all species and the sum of endemic species recorded from each island. Species Kauai Oahu Molokai Lanai Maui Hawaii H. akoko H. andrenoides z H. angustulus |} H. anomalus | H. anthracinus1 zz|z2 z H. assimulans |zz2 H. chlorostictus z H. coniceps zz H. connectens }z}zz3 z H. crabronoides z H. difficilis zzz z H. dimidiatus z H. dumetorum z H. facilis |||z H. filicum z H. finitimus | H. flavifrons4 z H. flavipes z|5 z H. fuscipennis |zzz H. gliddenae 6 H. haleakalae zz H. hilaris z||7 H. hirsutulus z H. hostilis z H. hula z H. inquilina z H. kauaiensis z H. kokeensis H. kona z H. kuakea H. kukui H. laetus zz|zz88 z H. longiceps zzzz8 H. mana H. mauiensis | HAWAIIAN HYLAEUS 5 Species Kauai Oahu Molokai