Temporal range: Ypresian–Recent
|Dipogon subintermedius, f|
Wasps in the family Pompilidae are commonly called spider wasps, spider-hunting wasps, or pompilid wasps. The family is cosmopolitan, with some 5,000 species in six subfamilies. Nearly all species are solitary (with the exception of some group-nesting Ageniellini), and most capture and paralyze prey, though members of the subfamily Ceropalinae are kleptoparasites of other pompilids, or ectoparasitoids of living spiders.
In South America, species may be referred to colloquially as marabunta or marimbondo, though these names can be generally applied to any very large stinging wasps. Furthermore, in some parts of Venezuela and Colombia, it is called matacaballos, or "horse killers", while in Brazil some particular bigger and brighter species of the general marimbondo kind might be called fecha-goela/cerra-goela, or "throat locker".
Like other strong fliers, pompilids have a thorax modified for efficient flight. The metathorax is solidly fused to the pronotum and mesothorax; moreover, the prothorax is best developed in Pompilidae and Scoliidae because wasps in these families use their forelegs to dig.
Pompilids typically have long, spiny legs; the hind femur is often long enough to reach past the tip of the abdomen. The tibiae of the rear legs usually have a conspicuous spine at their distal end. The first two segments of the abdomen are narrow, giving the body a slender look. The pompilid body is typically dark (black or blue, sometimes with metallic reflections), but many brightly colored species exist. From a lateral view, its pronotum looks rectangular and it extends back to the tegulae, near the base of the wings. Most species are macropterous (having long wings), but a few brachypterous (short-winged) and apterous (no wings) species are known.
Spider wasps are best distinguished from other vespoid wasps in having (in most species) a transverse groove bisecting the mesopleuron (the mesepisternal sclerite, a region on the side of middle segment of the thorax above the point where the legs join). Like other Vespoidea, they have antennae with 10 flagellomeres in the female and 11 in the male. Most Pompilidae have straight inner eye margins. The hind wings do not have a distinct claval lobe, but they have a distinctive jugal lobe. The hind leg has a tibial spur with a tuft or row of fine hairs. The legs are long and slender with the tips of the tibia (metatibia) long enough to extend beyond the tip of the abdomen (metasoma). Sexual dimorphism is not pronounced, although females are often larger than the males. Coloration and wing appearance vary greatly among the many species. General coloration is aposematic (warning off predators), generally based on black, often with markings of orange, red, yellow, or white. Larvae can also be identified by physical examination.
Currently, the Pompilidae are split unequally into six subfamilies throughout most of the world. Ceropalinae and Notocyphinae contain two genera each and occur in Central and South America and Asia. The Epipompilinae contain a single genus and occurs in the Neotropics, the Australasian region, and the Afrotropical region. The Ctenocerinae contain two genera in the Neotropics, four in Australia and 11 in Africa. Pepsinae and Pompilinae are the most diverse, and the remaining genera are split between them.
The oldest fossil currently known is an indeterminate fossil from the Early Eocene (Ypresian) Klondike Mountain Formation of Washington State, USA. Other fossil species are known from Dominican and Baltic ambers, the Florissant Formation and various other localities in Germany, France and Spain. Bryopompilus described from the mid Cretaceous Burmese amber was initially thought to belong to this family, however it was subsequently placed in its own family, the Bryopompilidae.
Ecology and behavior
Adult pompilids are nectar-feeding insects and feed on a variety of plants. Depending on genus and species, pompilids capture a variety of spiders for their larvae to feed on, covering nearly all free-living spider families, including tarantulas, wolf spiders (Lycosidae), huntsman spiders (Sparassidae), jumping spiders (Salticidae) (and baboon spiders (Harpactirinae), though any given pompilid tends to attack only a limited diversity of spiders.
A female wasp searches the ground and/or vegetation for a spider, and upon finding one, stings it, paralyzing the spider. The targeted spider typically isn't able to kill the wasp, because the wasp can just fly out of reach, so at best the spider fights fiercely to escape. Tarantula hawks (Pepsini) do not attack when adult tarantulas are close to or in their burrows. Instead, the wasps seek out adult males who have left their burrows in search of females to mate with. In the open the wasp first uses its wings to beat air over the tarantula, deceiving the tarantula into thinking that it being targeted by a large bird so the tarantula reacts by curling up to appear smaller and less noticeable, which in turn makes the tarantula defenseless against the wasp's attack. However, Brazilian Wandering spiders (Phoneutria) and their predators have a different interaction dynamic, and the spiders often manage to defeat the hunting wasp.
Once the spider is paralyzed, a female pompilid makes a burrow or flies or drags the spider to a previously made burrow. Because of the large body size of their prey, tarantula hawks usually will either construct burrows near the site of attack or use the host's own burrow or tunnel. Pompilids typically provide each of their larvae with a single prey/host, which must be large enough to serve as its food source throughout its development. Typically, a single egg is laid on the abdomen of the spider, and the nest or burrow is closed so the larva can develop without disruption by other parasites or scavengers. The female wasp may then engage in spreading soil or other changes to the area, leaving the nest site inconspicuous. One species of spider wasp protects its nests by putting dead ants into the outermost chamber, where the ants' chemicals deter predators.
The egg hatches and the larva feeds on the spider, breaking through the integument with its mandibles. As the larva feeds on its host, it saves the vital organs, such as the heart and central nervous system, for last. By waiting until the final larval instar, it ensures the spider will not decompose before the larva has fully developed. The larva has five instar stages before it pupates; no major morphological differences are noted between the first four instars, with the exception of size. At the conclusion of the final instar, the larva spins a durable silk cocoon, and emerges as an adult either later in the same season or overwinters, depending on the species and the time of year the larva pupates. Some ceropalines lay their egg on a still-active spider, only temporarily paralyzing it, and the wasp larva feeds externally by extracting hemolymph after the egg hatches. In time, the spider will die, and the mature wasp larva will then pupate.
The size of the host can influence whether the wasp's egg will develop as a male or a female; larger prey often yield the (larger) females. Pepsis thisbe of the southwestern United States exhibits a direct correlation between adult wasp body length and the weight of its host spider, Aphonopelma echina. Because the size of a P. thisbe adult is determined by the size of the host provided for it by its mother, the seasonal frequency of host sizes implicitly will determine the size variation in adult wasps.
In another study on Pepsis thisbe, chemosensory cues were shown to be used to detect specific hosts. Specific chemosensory cues attract the wasp to its prey, Aphonopelma echina, despite other host spiders of the same size and frequency being present. In studies on Pepsis grossa (formerly P. formosa), a pompilid of the southwestern United States, the wasps were found to have behavioral plasticity. Their hunting behavior concerning their host Rhechostica echina improved with experience. The time required to complete all behavioral components decreased with each spider killed.
Concerning mating behavior, males acquire perch territories to scan for incoming receptive females. In studies on the tarantula wasp Hemipepsis ustulata, larger males are more likely to acquire perch territories and territorial males appear to increase their chances of mating because receptive females fly to perch sites held by said males.
The Pompilidae produce a venom, delivered when they sting, containing a variety of powerful neurotoxins named pompilidotoxin (PMTX). These inhibit the inactivation of voltage-gated sodium channels, causing too much sodium to flow through neuron cell membranes, causing long bursts of nerve impulses (action potentials, and thus overstimulating these nerves. Alpha- and beta-PMTX are both small peptide chains of just 13 amino acids; alpha-PMTX has been studied in Anoplius samariensis, while beta-PMTX has been studied in Batozonellus maculifrons.
Schmidt pain index
In 1984, Justin O. Schmidt developed a hymenopteran sting pain scale, now known as the Schmidt sting pain index. In this index, a 0 is given to a sting from an insect that cannot break through human skin, a 2 is given for intermediate pain, and a 4 is given for intense pain. The scale rates stings from 78 different species in 42 different genera. Spider wasps of the genus Pepsis, also known as tarantula hawks, have a sting rating of 4. The sting is described as "blinding, fierce, and shockingly electric. A running hair dryer has been dropped into your bubble bath." Only the sting of the bullet ant, Paraponera clavata, is ranked higher, with a 4+ rating.
A Western Australian pompilid has captured a large huntsman spider.
The anaesthetised spider is carried up to a nest in the roof.
- "Pompilidae Spider-Hunting Wasp". NBN Atlas. Retrieved 10 August 2019.
- Costa, Fernando G.; Pérez-Miles, Fernando; Mignone, Antonio (April 2004). "Pompilid Wasp Interactions with Burrowing Tarantulas: Pepsis cupripennis versus Eupalaestrus weijenberghi and Acanthoscurria suina (Araneae, Theraphosidae)" (PDF). Studies on Neotropical Fauna and Environment. 39 (1): 37–43. doi:10.1080/01650520412331270945. ISSN 0165-0521. OCLC 231044349. Retrieved 20 April 2012.
- Pitts, James P.; Wasbauer MS & von Dohlen CD (2005). "Preliminary morphological analysis of relationships between the spider wasp subfamilies (Hymenoptera: Pompilidae): revisiting an old problem". Zoologica Scripta. 35 (1): 63–84. doi:10.1111/j.1463-6409.2005.00217.x.
- Evans, H.E.; Shimizu, A. (1996). "The evolution of nest building and communal nesting in Ageniellini (Insecta: Hymenoptera: Pompilidae)". Journal of Natural History. 30 (11): 1633–1648. doi:10.1080/00222939600770961.
- Goulet, H; Huber, JT, eds. (1993). Hymenoptera of the world: an identification guide to families. Agriculture Canada. pp. 202–205.
- Daly, Howell V.; Doyen, John T.; Purcell, Alexander H. (1998). Introduction to Insect Biology and Diversity. Oxford: Oxford UP. ISBN 978-0-19-510033-4.
- Archibald, S. B.; Rasnitsyn, Alexandr P.; Brothers, Denis J.; Mathewes, Rolf W. (2018-01-08). "Modernisation of the Hymenoptera: ants, bees, wasps, and sawflies of the early Eocene Okanagan Highlands of western North America". The Canadian Entomologist. 150 (2): 205–257. doi:10.4039/tce.2017.59. ISSN 0008-347X.
- Rodriguez, Juanita; Waichert, Cecilia; von Dohlen, Carol D.; Pitts, James P. (2017-10-11). Wong, William Oki (ed.). "The geological record and phylogeny of spider wasps (Hymenoptera: Pompilidae): A revision of fossil species and their phylogenetic placement". PLOS ONE. 12 (10): e0185379. doi:10.1371/journal.pone.0185379. ISSN 1932-6203. PMC 5636076. PMID 29020022.
- Rodriguez, Juanita; Waichert, Cecilia; von Dohlen, Carol; Poinar Jr., George; Pitts, James (2015). "Eocene and not Cretaceous origin of spider wasps (Pompilidae): fossil evidence from amber". Acta Palaeontologica Polonica. doi:10.4202/app.00073.2014.
- CSIRO Fact Sheet
- Spider Wasps Australian Museum Online
- "Dead-ant wall protects young spider wasps". Science News. 2014-07-07. Retrieved 2014-07-11.
- Staab, Michael; Ohl, Michael; Zhu, Chao-Dong; Klein, Alexandra-Maria (2014-07-02). "A Unique Nest-Protection Strategy in a New Species of Spider Wasp" (PDF). PLOS ONE. 9 (7): e101592. doi:10.1371/journal.pone.0101592. PMC 4079592. PMID 24987876.
- Punzo, F (2005). "Studies on the natural history, ecology, and behavior of Pepsis cerberus and P. mexicana (Hymenoptera: Pompilidae) from Big Bend National Park, Texas". Journal of the New York Entomological Society. 113 (1): 84–95. doi:10.1664/0028-7199(2005)113[0084:sotnhe]2.0.co;2.
- Punzo, F (1994). "The biology of the spider wasp, Pepsis thisbe (Hymenoptera: Pompilidae) from Trans Pecos, Texas. I. Adult morphometrics, larval development and the ontogeny of larval feeding patterns". Psyche. 101: 229–242. doi:10.1155/1994/70378.
- "Spider predators and parasites". Iziko Museums of Cape Town: museums.org.za. Retrieved 28 November 2006.
- Punzo, F.; Ludwig, L. (2005). "Behavioral Responses of Pepsis thisbe (Hymenoptera: Pompilidae) to Chemosensory Cues associated with host spiders". Journal of Insect Behavior. 18: 757–766. doi:10.1007/s10905-005-8738-0.
- Punzo, F.; Garman, B. (1989). "Effects of encounter experience on the hunting behavior of the spider wasp, Pepsis formosa (Say) (Hymenoptera: Pompilidae)". The Southwestern Naturalist. 34: 513–518. doi:10.2307/3671510.
- Alcock, J.; Kemp, J. (2006). "The behavioral significance of male body size in the Tarantula Hawk Wasp Hemipepsis ustulata (Hymenoptera: Pompilidae)". Ethology. 112: 691–698. doi:10.1111/j.1439-0310.2006.01204.x.
- Kawai N, Konno K (2004). "Molecular determinants of two neurotoxins that regulate sodium current inactivation in rat hippocampal neurons". Neurosci. Lett. 361 (1–3): 44–6. doi:10.1016/j.neulet.2004.01.006. PMID 15135889.
- Sahara Y, Gotoh M, Konno K, Miwa A, Tsubokawa H, Robinson HP, Kawai N (2000). "A new class of neurotoxin from wasp venom slows inactivation of sodium current". Eur J Neurosci. 12 (6): 1961–70. doi:10.1046/j.1460-9568.2000.00084.x. PMID 10886337.
- Schiavon, Emanuele; Stevens, Marijke; Zaharenko, André J.; Konno, Katsuhiro; Tytgat, Jan; Wanke, Enzo (2010). "Voltage-gated sodium channel isoform-specific effects of pompilidotoxins". FEBS Journal. 277 (4): 918–930. doi:10.1111/j.1742-4658.2009.07533.x. ISSN 1742-464X. PMID 20059541.
- Berenbaum, M (2003). "A Stinging Commentary". American Entomologist. 49 (2): 68–69. doi:10.1093/ae/49.2.68.
- "Tarantula Hawks Deliver The Big Sting - Wry Heat". Tucsoncitizen.com. 2010-07-16. Retrieved 2013-03-15.
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