Insect Pollinators of Carrots in Utah
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Utah State University DigitalCommons@USU All PIRU Publications Pollinating Insects Research Unit 4-1960 Insect Pollinators of Carrots in Utah George E. Bohart Utah State University William P. Nye Utah State University Follow this and additional works at: https://digitalcommons.usu.edu/piru_pubs Part of the Entomology Commons Recommended Citation Bohart, George E., and William P. Nye. 1960. Insect Pollinators of Carrots in Utah. Utah Agr. Exp. Sta. Bull. 419. 16 p. This Bulletin is brought to you for free and open access by the Pollinating Insects Research Unit at DigitalCommons@USU. It has been accepted for inclusion in All PIRU Publications by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. tt-1 o i~JJJ,t:,;~V\'" ""\;,../ . t ~:'~ .• I t by GEORGE E. ,'/ I OF AGRI CULTURE CKNOWLEDGMENTS are due M. D. Levin and L. R. Hawthorn, both of the Agricultural Research Service, who helped plan and carry ofA the experiments of which these observations are a part. S. F. McClellan, Takeshi Miura, and W. A. Trost, graduate students at Utah State Univer sity, made most of the many observations. Determinations of the carrot pollinators were made by taxonomic specialists of the Entomology Research Division and by ,V. D. Field, H. A. Scullen, R. M. Bohart, H. E. Evans, M. T. James, and the senior author. The authors are both entomologists with the Entomology Research Division, Agricultural Research Service, U. S. Department of Agriculture. They are stationed on the Utah State University Campus and work coop- eratiwly with the Agricultural Experiment Station. Title on cover picture should read' Left a drone fly (Tubifera tenax) one of·th ' abundan t and. eff1cient carrot' pollinatorse most o~ the experimental plots at Logan. U er ~1g?t, pollen-collecting honey bee. N~~e 1nt1mat~ contact of body and flower cluster. Lower :1ght, nectar-collecting honey bee. There 1S only slight contact between body and flower cluster. ABSTRACT N THE course of observation at Logan, Utah, on the occurrence and pollina I ting activities of insects on carrots grown for seed, 334 species represent ing 71 families, were collected. Most numerous in species were the hymenopterous families and superfamilies Sphecidae, Apoidea, Psammo charidae, Vespidae, and Ichneumonidae, and the dipterous families Syrphidae, Tachinidae, Bombyliidae, Stratiomyidae, and Sarcophagidae. Most numer ous in individuals were the dipterous families Syrphidae, Ceratopogonidae, Chloropidae, and Piophilidae and the coleopterous family Coccinellidae. Families and superfamilies represented by the most efficient pollinators were Apoidea, Sphecidae, Syrphidae, and Stratiomyidae. Abundance times effi ciency was used as a pollination index for each species. On this basis the most important genera of Apoidea were Apis: Andrena, Halictus, Chloralictus, and Colletes; of Sphecidae, Cerceris, Lindenius, Philanthus, Nysson, and Sceliphron; of Syrphidae, Syritta and Tubifera; of Stratiomyidae, Eulalia and Stratiomys. Honey bees (Apis mellifera L.) were efficient pollinators, but they were only minor factors in the Logan area because of their scarcity on carrot flowers. In most areas a combination of honey bee colonies adjacent to car rot seed fields and elimination of competing bloom may be the most practical method of increasing carrot pollination. -1- CONTENTS page Introduction .............................................................................................................. 3 Description of area.................................................................................................. 3 Characteristics of carrot flowers............................................................................ 3 Variety and abundance of pollinators.................................................................. 4 Efficiency of pollinators......... ................................................................................. 6 ~Iethods of increasing pollinators ........................... ~ ..................................... ~ ........ 10 Insects visiting carrot flowers in the vicinity of Logan, Utah, 1954-1957 ........ 10 Hymenoptera .................................................................................................... 10 Diptera ............... :.............................................................................................. 12 Coleoptera ........... .............................................................................................. 14 Lepidoptera ...................................................................................................... 15 Hemiptera ........... ............................................................................................. 15 IIollloptera ........................................................................................................ 15 Neufoptera ........................................................................................................ 15 Orthoptera .......................................................................................................... 16 Dermaptera ...................................................................................................... 16 Thysanoptera .................................................................................................... 16 INSECT POLLINATORS OF CARROTS IN UTAH by George E. Bohart and William P. Nye ROM 1954 to 1957 aspects of car on carrot flowers, can set a substan F rot pollination were studied at tial amount of seed, although not Logan, Utah. The results of the work nearly as much as the larger Diptera in 1954 were reported by Hawthorn and Hymenoptera. Seed yields were et aU The present paper discusses satisfactory in the open plots, but the occurrence and pollinating effi slightly better in plots caged with ciency of the many species of insects colonies of honey bees. In subsequent that visited flowers on the open plots years results of the first year were each year. generally substantiated. However, in That insect pollination is necessary 1957, when insect populations in the for satisfactory yields of carrot seed open plots were much lower than was clearly demonstrated by the work previously, there was a large gap be in 1954. It was also shown that tiny tween the yields in the open plots Diptera, which are usually abundant and those caged with honey bees. DESCRIPTION OF AREA HE work was carried on at three suburban development. In 1955 the T locations near Logan, each of plots were a mile farther east, more fering diverse habitats, for insects. isolated from the alkaline areas, and In 1954 and 1956 the plots were lo surrounded by alfalfa, grain, small cated a mile north of Logan, where orchards, and sagebrush. In 1957 the the surrounding land is used prin plots were a few miles south of Lo cipally for dairying; to the west there gan, where the surrounding land is were several artesian springs and more intensely farmed and the foot alkaline meadows and hummocks, hills and orchard areas are farther and to the east foothills with sage away than in the previous locations. brush, small orchards, and scattered CHARACTERISTICS OF CARROT FLOWERS ARROT pollen is abundant and accessible to all insects except those C readily accessible to all visitors. with long, slender tongues. The in Carrot nectar is not abundant but it dividual florets are tiny and easily is exposed on the petals and readily worked by minute insects. At the same time they are aggregated into 1 L. R. Hawhom, C. E. Bohart, and E. H. flat, compact heads affording support Toole. Carrot seed vield andgermina to larger insects. .It is not surprising, tion as affected by different levels of in therefore, that a diverse assemblage sect pollination. Amer. Soc. Hort.· Sci. Proc. 67:384-389. 1956. of insects is attracted to the flowers. -3- VARIETY AND ABUNDANCE OF POLLINATORS s indicated in the accompanying the same location and year. The 25 A list, 334 species of insects rep most abundant species in order of resenting 71 families were collected their abundance each year are shown on the carrot blossoms in the open in table 1. Except in 1957, the small plots and on small adjacent plantings syrphid fly, Syritta pipiens (L.), was used for other types of studies. Most by far the most numerous. The vari of the species were scarce or trans able populations of the other species ient and individually contributed from year to year illustrate how futile little pollination, although they ac it would be to count on consistent counted for a substantial percentage pollination by anyone species. Many of the total pollination. of the more abundant Diptera breed As might be expected, the different in wet and decaying vegetable mat species varied greatly in abundance ter. The availability of this material from location to location, from year varied greatly from place to place to year, and from week to week at and season to season, depending upon Table 1. Populations 0/ the 25 most abundant species 0/ insects on carrot flowers 0/ the open plots, Logan, Utah, (number per plot per observation) * Species 1954 1955 4 1956 1957 Average Syritta pipiens ......................... .478 274.0 264.0 11 257 Piophila casei .......................... 304 3.2 62.0 0 92 Hippodamia spp. ................... 14 1.8 0.5 283 75 Chrysomyza demandata ............ 270 12.7 2.4 0 71 Madiza glabra .......................... 168 18.6 95.4 0 71 Dasyhelea spp . .......................... 168 0.0 87.2 0 64 Leptocoris trivittatus