Nesting Habits of Some Hornet Species (Hymenoptera, Vespidae) in Northern Thailand
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Nesting Habits of Some Hornet Species (Hymenoptera, Vespidae) in Northern Thailand Masao Nakamura1 and Saowapa Sonthichai2 ABSTRACT Seven nests of four hornet (Vespa) species collected around Chiang Mai, northern Thailand were described. Species observed were: V. affinis (2 nests), V. mocsaryana (2), V. velutina (2), and V. tropica (1). Three species coexisted on the Campus of Chiang Mai University. First reliable record of the colony composition of V. mocsaryana was presented. All the nests had only one foundress queen in July/August (mid- to late polyethic stage). Key words: Vespa spp, nesting sites, Vespidae INTRODUCTION MATERIALS AND METHODS The vespid genus Vespa (hornets) is Study sites and methods principally Oriental and eastern Palearctic in Chiang Mai is located at ca. 18⁄N and has a distribution, and has the largest number of species tropical monsoon climate, with relatively distinct in hilly and montane regions in tropics and rainy and dry seasons. The material was collected subtropics from eastern Himalaya through in the rainy season. The Campus of Chiang Mai Myanmar and Thailand to southern China (van der University, where most of the nests were located, Vecht, 1957, 1959; Matsuura and Yamane, 1990; was 315 m in altitude, while a Karen village, Mae Carpenter and Kojima, 1997). The highest diversity Wang, where a nest of V. tropica was located, was in the nesting habit of hornets is also anticipated in around 1,000 m in altitude. this region (Nguyen and Carpenter, 2002), but Hornet nests found on trees and buildings information on their biology is quite restricted. and underground were recorded and photographed, Nesting biology of some hornet species then collected using an anesthetic, an insecticide around Chiang Mai, northern Thailand during late sprayer and protective suits after stuffing cotton in July and early August in 2001 were studied. Seven nest entrances. Returning wasps were netted for nests of four species of Vespa were collected and one hour after nest collection. Collected nests their nesting characteristics were observed and were carried to the room and cell maps (Yamane recorded. and Yamane, 1975) were taken to record colony contents. Identification of species was made, and the results were checked by Prof. Seiki Yamane of Kagoshima University. 1 Shinsakuragaoka 1-19-5, Hodogaya-ku, Yokohama-shi, 240-0036 Japan. 2 Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand. Received date : 13/02/04 Accepted date : 31/03/04 RESULTS approximately 4.5 cm thick. The V. mocsaryana nests had an envelope composed of longitudinal Nesting sites wide tunnels rather than ‘shells’, and was only 1.5 Nesting sites of the collected colonies are cm thick. The single underground nest of V. tropica given in Tables 1 (A-G) together with other was damaged when collected, and the size could biological information. All nests (two) of V. affinis not be measured; the envelope was like a cylinder (TH01-MN-01, -02) (Figure 1d, 1f) and two of V. made of sheets of waving paper and without distinct mocsaryana (-03, 04) (Figure 1a, 1c) were found ‘shells’. in the open sites. Both branch and structural nestings In terms of the number of combs and comb were recognized in these species. One of the nests size V. affinis constructed the largest nests, while of V. mocsaryana (-04) (Figure 1a) was located in V. tropica did the smallest. But in the number of a hidden site in a bamboo bush close to the ground. cells V. velutina rivalled V. affinis. The two V. velutina nests (-05, -06) were made under the eaves of university buildings (Figure 1b, Colony composition 1e). The single nest of V. tropica (-07) was found Colony composition of the seven nests was in soil of a rocky slope. given in Table 1 (A-F). In all the nests the founding In Chiang Mai University campus four queen was still alive; polygyny was not seen. In the nests of three species were collected. The bigger of foundress of V. tropica the wings were almost the two nests of V. affinis was only 60 m apart from worn out and the body shined black. a nest of V. velutina, and the distance between the The number of workers was large in V. two V. velutina nests was 80 m. affinis and V. velutina (1381-1457), while less The single nest of V. mocsaryana (-03) and than 300 were present in the nests of V. mocsaryana the two nests of V. velutina found on the university and V. tropica. A clear relation was seen between campus had no trace of structure constructed by the numbers of workers and cells. From a nest of the foundress, thus were suspected of having moved V. affinis a male and a new queen were collected, from the original place (nest relocation sensu by and in a nest of V. mocsaryana a male was seen. Matsuura, 1984 and Matsuura and Yamane 1990; In the three species (excluding V. tropica), or translocation of nest sensu by Edwards, 1980). the first comb (sometimes also second) almost No information was obtained on the original nesting ceased to be used with few eggs and young larvae. sites of these species. In V. tropica, however, the first comb was still Nests of two other species, V. mandarinia being used to rear young, the numbers of eggs and and V. soror, were sold at the markets around young larvae matching those in the second comb. Chiang Mai, but their origins (nesting sites) were not traced. DISCUSSION Nest structure The Campus of the Chiang Mai University Structure of envelope and comb in the four has an area of only approximately 2.9 km2, but species was summarized in Table 2. Several types harbours at least three species of hornet. Although of envelope were recognized. In V. affinis and V. the number represented only minor part of the velutina the envelope was composed of ‘shells’, whole hornet fauna in Thailand (13 species; giving a scalloped pattern. However, in the latter Carpenter and Kojima, 1997), the fact that three ‘shells’ were larger and less defined or wider than predaceous species with similar nesting sites in the former. In both species the envelope was coexisted in a small area might give one of the Table 1 Colony composition of the collected nests. 1-A. Vespa affinis: TH01-MN-01 (on a bamboo stem, at 1.5 m above ground; Mae Wang suburbs of Chiang Mai). Comb No. from Diameter of comb top (cm) Number of immatures: I-V indicate larval instars Number of cells Long Short Pupae V IV III II I Eggs Empty Total 1 20.0 18.0 5 5 2 0 0 0 2 458 472 2 25.0 19.0 92 14 19 5 2 5 5 447 586 3 25.0 23.5 138 28 42 70 25 26 58 304 701 4 28.0 24.5 238 74 61 74 27 38 69 298 879 5 32.5 27.0 382 98 68 194 72 64 104 142 1124 6 40.5 32.0 628(5)* 179 234 426 119 124 256 64 1958 7 35.0 28.5 473(16) 77 136 305 83 91 211 12 1376 8 24.0 20.5 17(2) 25 47 181 91 70 125 7 563 Total 1968(23) 500 609 1255 328 425 830 1732 7647 Adults. Foundress: 1, females: 1376, males: 3, new queen: 1 Numerals in parentheses: no. new queens 1-B. Vespa affinis: TH01-MN-02 (on the window frame; Campus of Chiang Mai Univ.). Comb No. from Diameter of comb top (cm) Number of immatures: I-V indicate larval instars Number of cells Long Short Pupae V IV III II I Eggs Empty Total 1 7.5 7.0 1 0 0 0 0 0 0 103 104 2 13.0 8.0 25 0 0 0 0 0 0 98 125 3 20.0 14.0 84 27 36 8 5 4 36 170 370 4 25.0 13.0 112 26 43 18 14 10 43 119 385 5 28.0 13.0 141 58 31 23 12 13 96 107 481 6 30.0 17.0 202 73 34 21 10 15 125 190 670 7 28.0 15.0 111 71 35 18 12 33 94 61 454 8 20.0 11.0 51 42 36 38 18 27 51 30 301 9 6.0 5.0 0 0 0 0 0 1 12 28 41 Total 727 297 215 126 71 103 457 906 2913 Adults. Foundress: 1, females: 486, males: 0, new queen: 0 1-C. Vespa mocsaryana: TH01-MN-03 (on the ceilings of a building; Campus of Chiang Mai Univ.). Comb No. from Diameter of comb top (cm) Number of immatures: I-V indicate larval instars Number of cells Long Short Pupae V IV III II I Eggs Empty Total 1 8.0 7.0 30 10 9 6 5 3 7 0 70 2 12.0 12.0 116 50 21 19 16 11 52 0 285 3 13.5 13.5 129 70 42 41 18 20 69 0 389 4 10.0 10.0 64 30 30 27 20 20 25 3 219 Total 339 160 102 93 59 54 153 3 963 Adults. Foundress: 1, females: 230, males: 0, new queen: 0 1-D. Vespa mocsaryana: TH01-MN-04 (in bamboo bush, at 1.0 m above ground; Tha Tarn; suburbs of Chiang Mai). Comb No. from Diameter of comb top (cm) Number of immatures: I-V indicate larval instars Number of cells Long Short Pupae V IV III II I Eggs Empty Total 1 12.5 11.0 86 28 21 18 13 12 32 25 235 2 15.5 15.0 135 49 45 34 33 25 90 3 414 3 16.5 15.0 178 56 49 51 27 38 130 2 531 4 7.5 7.5 0 19 19 14 25 28 36 1 95 Total 399 138 134 117 98 103 288 31 1275 Adults.