The authors have declared that no competing interests exist.
Conceived and designed the experiments: MS AMK. Performed the experiments: MS. Analyzed the data: MS MO. Contributed reagents/materials/analysis tools: MS MO CDZ AMK. Contributed to the writing of the manuscript: MS MO CDZ AMK. Described the species: MO.
Hymenoptera show a great variation in reproductive potential and nesting behavior, from thousands of eggs in sawflies to just a dozen in nest-provisioning wasps. Reduction in reproductive potential in evolutionary derived Hymenoptera is often facilitated by advanced behavioral mechanisms and nesting strategies. Here we describe a surprising nesting behavior that was previously unknown in the entire animal kingdom: the use of a vestibular cell filled with dead ants in a new spider wasp (Hymenoptera: Pompilidae) species collected with trap nests in South-East China. We scientifically describe the ‘Bone-house Wasp’ as
Natural selection of life-history strategies results in increased individual fitness by ensuring successful reproduction, but reproductive strategies in animals vary widely
Examples of the latter group are the Pompilidae, a cosmopolitan family of spider-hunting wasps, of which the most well-known members are the eye-catching tarantula hawks of the New World genus
Species of the genus
In this paper we describe
Necessary permits to conduct field work were obtained from the Administration Bureau of the Gutianshan National Nature Reserve.
This study was carried out in the Gutianshan National Nature Reserve (GNNR) (29°14′ N/118°07′ E), Zhejiang Province, South-East China
In 2008, the ‘BEF-China’ project established a total of 27 study plots across the entire GNNR, each comprising 30 m×30 m, along gradients of tree species richness and forest age that we worked on in this study. For detailed descriptions of the study plots including maps, geological information and exhaustive botanical details we refer to Bruelheide et al.
Nests of solitary cavity-nesting wasps were collected in the 27 plots with trap nests from September 2011 to October 2012. In each plot, two wooden posts with four trap nests, each consisting of a plastic tube (length: 22 cm, diameter: 12.5 cm) filled with
(A) Exposed trap nest in the Gutianshan National Nature Reserve, the type locality of
For every nest we recorded the number of brood cells and parasitized brood cells. Length and diameter of nests were measured with a caliper. After eclosion, we identified all species with the help of taxonomic experts. From all nests containing a vestibular cell filled with dead ants, we randomly selected 26 for ant species identification. Voucher specimens were deposited at the University of Freiburg, Germany.
Analyses were done with the software R 3.0.2
The general terminology in pompilid taxonomy and morphology is based on Day
The electronic edition of this article conforms to the requirements of the amended International Code of Zoological Nomenclature, and hence the new names contained herein are available under that Code from the electronic edition of this article. This published work and the nomenclatural acts it contains have been registered in ZooBank, the online registration system for the ICZN. The ZooBank LSIDs (Life Science Identifiers) can be resolved and the associated information viewed through any standard web browser by appending the LSID to the prefix “
In total, we collected 829 nests of cavity-nesting wasps with 1929 brood cells belonging to 18 species (see
(A) Overview of a nest. Individual brood cells are separated by thin walls of soil material. (B) The nest is closed by a vestibular cell filled with dead ants. (C) Contents of a vestibular cell.
Family | Species | Nests | Brood cells |
Pompilidae | 2 | 8 | |
1 | 4 | ||
8 | 79 | ||
2 | 4 | ||
73 | 213 | ||
4 | 11 | ||
2 | 8 | ||
Sphecidae | 3 | 5 | |
156 | 199 | ||
Vespidae | 1 | 1 | |
1 | 2 | ||
4 | 14 | ||
548 | 1340 | ||
1 | 1 | ||
1 | 1 | ||
18 | 24 | ||
1 | 2 | ||
3 | 13 |
Pompilidae were identified by Raymond Wahis (Liege, Belgium), Sphecidae by Michael Ohl (Berlin, Germany) and Vespidae by Tingjing Li (Chongqing, P.R. China).
The 26 vestibular cells examined contained up to 13 ant individuals (mean: 4.9±2.6). All ant specimens were in good condition and could be identified to nine different species (see
Rearing of the nests with the ant-filled vestibular cell revealed an undescribed species of Pompilidae. Only seven of the 213 brood cells belonging to this species were parasitized (3%): four by an undescribed species of
The sympatric cavity-nesting wasp community is exemplified by
Variable | Estimate ± SEM | z | P |
Group | 2.01±0.54 | 3.75 | <0.001 |
Brood cells | −0.0075±0.0084 | −0.89 | 0.37 |
The new species clearly belongs to the genus
Ohl, 2014 (
(A, C) dorsal habitus, (B, D) right forewing, (E) head in frontal view, (F) genitalia in ventral view, slightly spread to show major elements. Scale bars: (A, C) 5.0 mm, (B, D) 2.0 mm, (E, F) 0.6 mm. Photographs: Bernhard Schurian (A–E), Birger Neuhaus (F).
The new species is named after the Latin ‘ossarium’, which means bone-house or ossuary. An ‘ossarium’ is a covered site, where human remains are deposited. The species name is an allusion to the unusual nesting strategy of the new species, which closes the nest with a vestibular cell filled with dead ants. This reminds us of historical bone-houses in monasteries and graveyards, which over time were filled with piles of human bones. The new name is a noun in apposition.
As a common name for
Known only from South-East China.
The main differences between the two species are (character states of
Total body length 8.9–15.2 mm, forewing length 7.4–13.3 mm.
Integument totally black. Beard and labral setae golden, ochraceous or coppery, setae otherwise mostly whitish.
Wings overall hyaline with faint greyish tinge, which is more dominant in large specimens. Forewing with narrow, indistinct fuscous marking along transverse section of at least longitudinal vein M, in some specimens also along cu-a and transverse section of Rs. Forewing also with large, fuscous marking occupying most of submarginal cells II and III, basal portion of marginal cell, and distal portion of discoidal cell II.
Frons densely, rather regularly punctate. Remaining head surface with fine, dense, shallow punctures and interspersed with widely spaced macropunctures. Pronotum and mesoscutum finely, densely punctate, mesosomal dorsum microsculptured otherwise. Mesosomal sides microsculptured, with widely spaced macropunctures. Upper part of metapleuron with transverse, coarse striae. Lateral portion of metanotum shining, with oblique striae. Propodeal dorsum miscrosculptured, with setiferous macropunctures in posterior half only. Metasoma microsculptured, dull.
Lower frons, basal half of mandible, gena, lower portion of mesosomal pleura, coxae, and posterolateral portion of propodeum with appressed, dense, silvery pubescence. Long ochraceous setae on outer mandibular surface and along anterior margin of clypeus. Gena, prosternum, forecoxa, propodeum posteriorly and tergum I with markedly long, silvery setae; similar but shorter setae on vertex, thoracic dorsum and mid and hindcoxae.
Head slightly broader than long (1.1–1.3). Inner eye orbits rather strongly converging above: upper, middle and lower interocular distances 6.5: 10: 10. Length of flagellomere I 4.9–5.4x as long as wide.
Structurally otherwise apparently identical to
Overall similar to female, except for: Total body length 6.6–9.8 mm, forewing length 5.9–8.3 mm.
Integument totally black, except for the following: clypeus ivory white with black basal marking of varying size; labial and maxillary palps, tibial spurs and foretibia and tarsi below ochraceous. In some specimens, pronotum with brownish transverse band. Body setae mostly whitish.
Wings hyaline, markings absent except for faint longitudinal marking in submarginal cells II and III, in a few larger males also in marginal cell and discoidal cell I.
Genitalia (
Structurally otherwise apparently identical to
All specimens have been reared from trap nests (
The majority of the paratypes will be deposited in the Insect Collection of the Institute of Zoology, Chinese Academy of Sciences, Beijing, China, along with the holotype. The remaining paratypes will finally remain in the collections of the Museum für Naturkunde, Berlin, Germany, and pairs will also be deposited in the Natural History Museum, London, UK, the American Museum of Natural History, New York, USA, the Smithsonian Institution, Washington DC, USA, the California Academy of Sciences, San Francisco, USA, the Utah State University, Logan, USA, and the collection of the Institute of Earth and Environmental Sciences, University of Freiburg, Germany.
We report here on a unique and effective nest-protecting strategy, the construction of a vestibular cell filled with dead ants in a new spider wasp. Vestibular cells occur commonly in solitary Hymenoptera
This scent camouflages nests against natural enemies which search their host by scent, as CCHs are known to release behavioral reactions without tactile interactions
Although some cavity-nesting wasp species are known to incorporate arthropod fragments into nest construction
(DOCX)
We are grateful to the administration of the Gutianshan National Nature Reserve and the BEF-China consortium, Sabine Both, Xiaojuan Liu, Keping Ma, Helge Bruelheide and Bernhard Schmid for their support. The latter two, Christoph J. Kleineidam and Tamar Marcus gave helpful comments on the manuscript. Merten Ehmig provided photographs for Figure 2A and 2B, Bernhard Schurian for Figure 4A–E, and Birger Neuhaus for Figure 4F.