Biology of the bee genus Proteriades Titus (Hymenoptera: Megachilidae)
1978; Kansas (Central States) Entomological Society; Volume: 512; Linguagem: Inglês
ISSN
1937-2353
Autores Tópico(s)Fern and Epiphyte Biology
Resumo?Nests of 15 species of the bee genus Proteriades Titus are de scribed. These descriptions include the nesting site, cell structure, provisions, sex ratios, supercedure, cocoons, and nest associates. One specific name, P. mazourka (Michener), was synonymized with P. mojavensis (Michener), as they were male and females of the same species. Nests of 11 species are described for the first time. Nesting habits of Proteriades are compared with those of related genera. Proteriades Titus is a moderate-sized genus of megachilid bees, with 32 described species assigned to six subgenera. The distribution of these bees is primarily our southwestern states but one species has been reported as far east as South Dakota (LaBerge, 1973). Most species appear infrequently, and collect pollen from flowers of the borage genus Cryptantha (Hurd and Michener, 1955). The systematic concept of the genus has changed since the revision of Timberlake and Michener (1950), and Proteriades presently includes sub genera formerly placed in Hoplitis Klug (Michener and Sokal, 1957). Also two new species have been described (Parker, 1976, 1977). It has been reported that these bees collect pollen exclusively from Cryptantha flowers?with the aid of the unique hooked hairs on their mouthparts (Hurd and Michener, 1955). Since the generic concepts have changed and the genus now includes species without hooked hairs on their mouthparts (Hoplitina and some females of Acrosmia), the assumed fidelity of this genus to Cryptantha is no longer valid. The nesting habits of Proteriades species have been reported on briefly. Michener (1943) noted that P. xerophila (Cockerell) utilized old nests of Anthophora linsleyi Timberlake. Cells of the latter were dug from a clay bank in southern California by G. E. Bohart. Hurd and Michener (1955) observed P. remotula (Cockerell) and P. deserticola Timberlake and Mich ener entering burrows in the ground. The latter species nested in hard packed sandy loam and gathered pollen from Cryptantha barbigera (A. Gray) Greene. Parker and Bohart (1966, 1968) reported nests of nine species that were obtained from old galls on Tetradymia, burrows in stems of Tetradymia and Oenothera, or trap stems. Thorp (1968) described a nest of P. bunocephala (Michener) from a twig nest, and Parker (1976, 1977) described nests of two new species that were reared from trap stems. This content downloaded from 157.55.39.54 on Sat, 02 Jul 2016 05:18:57 UTC All use subject to http://about.jstor.org/terms 146 JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY The material on which this paper is based was obtained through in tensive trap nest studies carried out over a 15-year period. The number of Proteriades nests recovered is small when compared to other groups of trap-nesting bees and with the exception of P. bullifacies the yield of Proteriades nests has been less than 1% of the utilized traps. Nest descrip tions of the species listed earlier (Parker and Bohart, 1966, 1968) are in cluded here along with nest descriptions of six additional species. Trap stems are made from dead stalks (42 cm long) of elderberry (Sam bucus) or raspberry (Rubus). At the top of each stem a hole was drilled into the pith to a depth of 7 cm or more, referred to as the end hole. Three sizes of end holes were made using a 3-, 6-, or 9-mm drill bit. Two holes were drilled horizontally in each stem to a depth of 1 cm or more (limited by stem diameter) referred to as the side hole. The side holes were 13 cm apart and on opposite sides of the stem with the first hole drilled 15 cm from the stem top. Two sizes of side holes were made using a 3or 6-mm drill bit. Traps were set out in March at lower elevation in southern sites and in May in more northern sites. At each site 100-200 stems were stuck vertically into the ground about 3 m apart. The hole-size percentages were : end holes?25%, 3 mm; 50%, 6 mm; 25%, 9 mm; side holes?50%, 3 mm; and 50%, 6 mm. The traps were picked up in October or November and stored in an unheated building until December and then transferred to a 5?C cold room. Subsequently the traps were opened, their contents re corded, and placed in 00 gelatin capsules. In April the capsules were incu bated at 20?C and checked twice daily for emergence. When insects emerged the capsules were dated and frozen, their contents readily mounted and labeled later. Pollen identification of provisions in trap nests was done utilizing sam ples from pollen balls (if available) and pollen remaining on the cell walls in cases where the larvae had consumed the provisions. Small squares of glycerin jelly (Beattie, 1971) were daubed against the cell walls to obtain pollen grains stuck into the pith. (Trap nests with different bee species nesting below the Proteriades nests were not utilized to avoid contamina tion.) An importance value for each pollen species was calculated by adding the separate values of the relative percent of grains counted, the volume, and the frequency of occurrence in cells and nests (Curtis and Mclntosh, 1951). The maximum value for each species is 300. This index does not give a preference rating for pollen plants simply because no observations were made on the availability of each pollen species during nest provisioning. Proteriades (Hoplitina) bullifacies (Michener) (Figs. 1, 2) Though P. bullifacies is rare in collections, it can be commonly collected via trap stems. During the years I have set out trap stems significant fluctu This content downloaded from 157.55.39.54 on Sat, 02 Jul 2016 05:18:57 UTC All use subject to http://about.jstor.org/terms VOLUME 51, NUMBER 2 147 ations have occurred in populations of this species. In 1963 traps placed at Patrick, Nevada (east of Reno), yielded no nests of P. bullifacies. The next year at this same location a similar number of traps contained 141 nests (43% of the utilized borings). In 1973 traps set out at Winnemucca sand dunes (10 mi N Winnemucca, Nevada) contained 194 nests of this species (82% of the utilized holes). The next year at this same location a similar number of traps held no nests of P. bullifacies. In the years when this bee was present its nests were collected at several locations. The localities and and years its nests were collected are listed in Table 1. Nest construction.?The 606 nests collected contained 2,414 cells. Fe males nested predominately in 3-mm holes in the trap stems since 53% of all holes utilized by these females were of this size. Of the two hole sizes (3 or 6 mm) made on the sides of the stems, this species utilized 91% of the 3 mm size. Nests made in the end holes were most numerous in the 6-mm size (76%). The percent of nests made in other sizes of end holes were 9% in the 9 mm and 15% in the 3 mm. In addition to trap stems, this bee constructed its nests in old galls or beetle borings in stems of Tetradymia canescens DC. The nests contained an average of four cells each, the number ranging from 1-23. Generally the females utilized the boring without any modifica tions except for the usual cleaning out of loose pith, though many nests were initiated without lining the inner end of the boring with nest-building material. Occasionally nests were initiated at several levels above the inner end. In these instances, the bottom of the first cell was made by cement ing sand grains together with masticated plant parts into discs 1-2 mm thick and saucer-shaped in profile. Usually the top of such a disc was composed of a thin layer of masticated plant parts which covered most of the sand grains. In some of the longer borings cells were made against the side walls in a spiral and in other trap stems the boring was divided longitudinally by a partition with cells on either side of it. In such borings the cells were dome shaped with the space between them filled with sand and masticated leaf material. Cells averaged 6 mm long but the range was 4-8 mm. The entrance plugs were usually made flush with the en trance hole but some females placed these plugs just below the opening. Entrance plugs were composed of sand grains and masticated leaf material but more plant material was used than in the discs separating the cells. Gen erally the entrance plug was about 4-mm thick and in some nests distinct layers of plant material separated the discs of sand grains. Provisions.?Pollen balls usually conformed to the shape of the cell bot tom and filled only three-fourths of the cell. The host egg was deposited at and across the top of the ball. Females of P. bullifacies are specialists on Phacelia as every cell in all nests examined contained mostly this pollen? 93 to 100%, Table 2. However, other pollens, Salsola, Gilia, and some com posites were found in small amounts but possibly came from nectar plants. One, Salsola, was more numerous (Table 2). This content downloaded from 157.55.39.54 on Sat, 02 Jul 2016 05:18:57 UTC All use subject to http://about.jstor.org/terms 148 JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY Fig. 1. A multicelled end hole nest of P. bullifacies. Fig. 2. A cocoon of P. bulli facies. Note small fecal pellets. Fig. 3. A three-cell nest of P. mojavensis made in a side hole. Note the small sand grains. Fig. 4. Plug in entrance to a side hole utilized by P. mojavensis. This content downloaded from 157.55.39.54 on Sat, 02 Jul 2016 05:18:57 UTC All use subject to http://about.jstor.org/terms Table 1. Summary of nests, cells, provisions, and nest associates of Proteriades bullifacies (Michener) from trap stems placed at Nevada and California sites. Site Mortality of Nests Cells immature Sex ratio (no.) (no.) stages (%) ( $ ; 9 ) Cells with nest associates (%) Type of pollen collected (%) of total grains < O r c
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