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Effects of different habitats on the productivity of the native paper wasp Polistes fuscatus and the invasive, exotic paper wasp P. dominulus (Hymenoptera: Vespidae).
| Content Provider | Semantic Scholar |
|---|---|
| Author | Gamboa, George J. Austin, Julie A. Monnet, Kimberley M. |
| Copyright Year | 2005 |
| Abstract | We examined the colony productivities of the native paper wasp, Polistes fuscatus (Fab.),(Hymenoptera: Vespidae), and the invasive, exotic paper wasp, P. dominulus (Christ), in oak forest, oak forest-old field ecotone, and old field habitats at the Oakland University Preserve in Rochester, Michigan from 2003 to 2005. Both species of paper wasps exhibited significant differences in colony productivity among the three habitats. Generally, colonies were the most productive in the old field habitat and the least productive in the oak forest habitat. Colonies of P. dominulus were significantly more productive than comparable colonies of P. fuscatus in all three habitats. There was no evidence that P. fuscatus was more competitive with P. dominulus in any of the three habitats. Thus, our results do not support the suggestion of Gamboa et al. (2004) and Liebert et al. (2006) that P. fuscatus may be more competitive with P. dominulus in less disturbed or forest habitats than in urban and rural habitats. ____________________ The invasive, European paper wasp, Polistes dominulus (Christ) (Hymenoptera: Vespidae), was first reported in the United States in 1978 (Eickwort 1978) and in Michigan in 1995 (Judd and Carpenter 1996). Since its introduction, P. dominulus has rapidly replaced the only native species of paper wasp, Polistes fuscatus (F.), in many urban and rural areas of southeastern Michigan (Gamboa et al. 2002). P. dominulus also appears to be at least partially supplanting P. fuscatus in Massachusetts (A. Liebert, pers. comm.), New York (E. Tibbetts and N. Stamps, pers. comm.), and southern Ontario, Canada (G. Otis, pers. comm.). P. dominulus is thought to be supplanting P. fuscatus by indirect (exploitative) competition although the critical resources in this competition are unknown (Gamboa et al. 2004). Gamboa et al. (2004) speculated that the two species may be competing for nest sites. Polistes dominulus is much more productive than P. fuscatus in urban habitats: both singleand multiple-foundress colonies of P. dominulus are significantly larger than comparable colonies of P. fuscatus (Gamboa et al. 2004). A major factor that contributes to the high productivity of P. dominulus is its short larval and pupal stadia, which enables it to produce its first workers significantly earlier than P. fuscatus. P. dominulus enjoys other advantages over P. fuscatus including higher per capita foraging rates, greater survivorship, lower rates of parasitism by Strepsiptera, and lower conspecific usurpation pressures (Gamboa et al. 2004). Although P. dominulus appears to be replacing P. fuscatus in many urban and rural areas, it’s unknown whether P. dominulus will completely displace P. fuscatus throughout its range. Gamboa et al. (2004) and Liebert et al. (2006) suggested that P. fuscatus may persist in certain habitats in which it might be more competitive with P. dominulus. For example, P. fuscatus may be more competitive with P. dominulus in less disturbed or forest habitats than in urban and rural areas. Liebert et al. (2006) also suggested that P. fuscatus could persist in the northern regions of its range if it was better able to tolerate colder 1Department of Biological Sciences, Oakland University, Rochester, MI 48309. 1 Gamboa et al.: Effects of Different Habitats on the Productivity of the Native P Published by ValpoScholar, 2005 2005 THE GREAT LAKES ENTOMOLOGIST 171 temperatures during winter diapause than P. dominulus. There is presently, however, no evidence to support these suggestions. We designed our study to answer two questions. First, does habitat type affect productivity in P. fuscatus and P. dominulus? Second, if there are productivity differences among different habitats in the two species, is there evidence that P. fuscatus is more competitive with P. dominulus in a particular habitat? The latter question bears directly on the question of whether P. fuscatus will be completely replaced by P. dominulus. METHODS Our study was conducted in 2003, 2004, and 2005 at the Oakland University Preserve in Rochester, Michigan. The Preserve, which contains approximately 110 acres, consists primarily of a forest dominated by white, red, and black oak trees (Larch and Sakai 1985). These overstory trees have a mean age of approximately 125 years, and thus large areas of the Preserve have been undisturbed for extensive periods of time (Larch and Sakai 1985). The Preserve also contains several small (<5 acres) old fields, which consist primarily of grasses (Poaceae), weedy, shade-intolerant woody plants, and various wildflowers (Larch and Sakai 1985). Plywood wasp nestboxes (Judd 1988) were first placed at the Preserve in 1981, and Polistes spp. have annually occupied the nestboxes since then. Both P. dominulus and P. fuscatus commonly nest in cavities such as pipes, electrical boxes, bird boxes, mailboxes, etc., which are nest sites similar to our plywood nestboxes. Nestboxes are located in three different habitats: the oak forest, the interface between the forest and old fields (ecotone), and the old fields. Nestboxes in the forest receive no direct sun, nestboxes in the ecotone receive either morning or afternoon sun, and nestboxes in the old fields receive both morning and afternoon sun. Forest and old field nestboxes were located from 10 – 40 m into the forest and 10 – 50 m into old fields, respectively. Ecotone nestboxes were in the old fields within 2 m of the forest edge. Foundresses of P. fuscatus and P. dominulus initiated colonies in the nestboxes in midto late April. All foundresses were marked with Testors enamels (Testors Corp.) for individual identification about three weeks after nest initiation. We surveyed nestboxes weekly throughout the preworker phase of the colony cycle and every two to three weeks during the postworker phase of the colony cycle. During surveys, we recorded the species, number, and identities of foundresses in each nestbox. After the end of the colony cycle when combs no longer contained adults, we brought the nestboxes into a laboratory, removed the combs from the nestboxes, and counted the number of cells and the number of cells with meconia in each comb as an estimate of colony productivity. The number of cells and the number of meconial cells, both of which are highly positively correlated with the number of adults in a colony, have been commonly used as estimates of colony productivity in Polistes (Gamboa et al. 2002, 2004). In 2003, 2004, and 2005, there were 84 (35 P. fuscatus, 49 P. dominulus), 91 (47 P. fuscatus, 44 P. dominulus), and 81 (33 P. fuscatus, 48 P. dominulus) colonies, respectively, in the nestboxes. In the late summers of 2002 and 2003, we removed about a third and half of the P. dominulus colonies, respectively, from the Preserve because we were concerned that we were losing our population of P. fuscatus (see Liebert et al. 2006). In order to minimize uncontrolled variables that might affect colony productivity, we used the following matched comparisons for statistical analyses. To determine if habitat types affect productivity, we compared the productivity of a forest colony with the nearest conspecific ecotone colony and nearest conspecific old field colony that had the same number of foundresses. To determine if the relative productivities of P. fuscatus and P. dominulus differed among the three habitat types, we compared the 2 The Great Lakes Entomologist, Vol. 38, No. 2 [2005], Art. 7 https://scholar.valpo.edu/tgle/vol38/iss2/7 172 THE GREAT LAKES ENTOMOLOGIST Vol. 38, Nos. 3 & 4 productivity of a P. fuscatus colony with the nearest colony of P. dominulus that was in the same habitat and had the same number of foundresses. Our use of matched data sets controlled for both spatial proximity and foundress number and, in heterospecific comparisons, habitat. All statistical tests are two-tailed, and the sample size (N) is the maximum number of matched sets of colonies available for statistical analysis. RESULTS Both species of Polistes exhibited marked differences in colony productivity in different habitats. P. fuscatus displayed significant differences in productivity among the three habitats for mean number of cells (P = 0.0005) and mean number of meconial cells (P = 0.022; Tables 1, 2). P. fuscatus colonies in the forest habitat were significantly less productive than comparable conspecific colonies in the ecotone and old field habitats (P < 0.01 for mean number of cells and P < 0.02 for mean number of meconial cells). However, colonies of P. fuscatus in the ecotone and old field habitats did not differ significantly (P > 0.05) in either mean number of cells or mean number of meconial cells (Tables 1, 2). Polistes dominulus also displayed significant differences in colony productivity among the three habitats for both mean number of cells (P = 0.003) and mean number of cells with meconia (P = 0.015; Tables 1, 2). Colonies of P. dominulus in the old field habitat were significantly more productive (P < 0.01 for mean number of cells, P < 0.02 for mean number of meconial cells) than comparable conspecific colonies in ecotone and forest habitats (Tables 1, 2). P. dominulus colonies in all three habitats differed significantly from each other in mean number of meconial cells (P < 0.02) although forest and ecotone colonies did not differ significantly in mean number of cells (P > 0.05; Tables 1, 2). Polistes dominulus was significantly more productive than P. fuscatus in all three habitats for both mean number of cells and mean number of meconial cells (Table 3). Depending on the habitat, P. dominulus colonies had productivities that were 2.29 to 4.2 times that of comparable colonies of P. fuscatus (Table 3). Moreover, there was no evidence that P. fuscatus was more competitive with P. dominulus in a particular habitat. The productivity ratios of P. dominulus vs. P. fuscatus did not differ significantly among the three habitats for either mean number of cells |
| Starting Page | 170 |
| Ending Page | 176 |
| Page Count | 7 |
| File Format | PDF HTM / HTML |
| Volume Number | 38 |
| Alternate Webpage(s) | https://scholar.valpo.edu/cgi/viewcontent.cgi?article=2134&context=tgle |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
