Anochetus bytinskii

Every Ant Tells a Story - And Their Stories Are Here
Jump to navigation Jump to search


Anochetus bytinskii
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Anochetus
Species: A. bytinskii
Binomial name
Anochetus bytinskii
Kugler, J. & Ionescu-Hirsch, 2007

Anochetus bytinskii casent0281012 p 1 high.jpg

Anochetus bytinskii casent0281012 d 1 high.jpg

Specimen Labels

The nests of A. bytinskii are subterranean. Brood-containing cocoons (N=20) were found inside a chamber of such a nest together with workers, but without eggs and larvae. They were kept in the laboratory till the emergence of the last adults, all males, over a period of 27 days. This species is apparently cryptobiotic as alluded by the subterranean nature of the nests that, together with their openings, were often found under large stones. (Kugler and Ionescu-Hirsch 2007)

Identification

Kugler and Ionescu-Hirsch (2007) - We compared workers, a gyne and males of A. bytinskii with the same casts of Anochetus ghilianii, Anochetus sedilloti and Anochetus traegaordhi, whenever available and with A. evansi (based on the literature only: Crawley (1922) and Brown (1978)). The main differences among workers of these species are presented in the key (see link below). However, as A. traegaordhi is apparently a complex of several Afrotropical species (Bolton, personal communication), we based the key on the East-African material only, including the holotype, and did not include the studied specimens from Congo, the latter not keying well to any of the species.

Workers: A. bytinskii is most similar to the East African A. traegaordhi, and the two species share similar head, antenna and mandible shape, and pattern of pilosity distribution. A. bytinskii has a distinctly weaker sculpture especially on the head and propodeum, much shorter frontal striation (L < 0.19 as compared to L > 0.35 of HL), and noticeably smaller eyes (L < 0.23 mm as compared to L > 0.24 mm).

Gyne: A. bytinskii differs from A. ghilianii and A. traegaordhi by the rounded, slightly convex declivity of propodeum as compared to a transversely concave declivity; weak and short frontal striation, as compared to a strong striation, extending to the posterior ocellus (Fig. 12); and the rounded petiolar node summit, as compared to an indented petiolar node summit in the other two species (Figs. 13, 14). A. bytinskii differs from A. sedilloti (based on the descriptions by Forel (1900) and Finzi (1939)) by the mostly smooth and shiny pronotum, mesopleuron and metapleuron as compared to a longitudinally striate pronotum and coarsely striated mesopleuron and metapleuron.

Male: A. bytinskii differs from A. ghilianii by the smaller ocelli, less bulky propodeum, cylindrical gaster (slightly conical in A. ghilianii), and distinctly fewer erect antennal hairs. The petiolar node is dorsally shallowly concave with rounded summit in lateral view in A. bytinskii, whereas bidentate with deeply incised dorsal margin, and with sharply pointed summit in lateral view in A. ghilianii (Figs. 15 and 16). The subgenital plate of A. bytinskii is posteriorly strongly narrowed, whereas that of A. ghilianii has elongated triangular shape without becoming caudally digitiform (Fig. 17). In dorsal view the concavity of the paramere is markedly narrower in A. bytinskii and in lateral view the caudally constricted part of the paramere is about twice as narrow as that of A. ghilianii (Fig. 18). A. bytinskii differs from A. sedilloti (Forel, 1907; Santschi, 1907) in the dorsal margin of the petiolar node concave as compared to convexly rounded; and subgenital plate apically digitiform as compared to rectangular, linguiform.

Keys including this Species

Distribution

The distribution of A. bytinskii is limited to the northern half of Israel, from the Karmel Ridge and the Lower Galilee to the Foothills of Judea. (Kugler and Ionescu-Hirsch 2007)

Distribution based on Regional Taxon Lists

Palaearctic Region: Israel (type locality).

Distribution based on AntMaps

AntMapLegend.png

Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Not much is known about the the biology of Anochetus bytinskii but we can presume that its biology is similar to other Anochetus species. The following account of Anochetus biology is modified from Brown (1968):

Habitat. The places where Anochetus live are varied. Where they penetrate into the temperate zone, most species excavate nests in the earth. Occasionally the nest is dug under a covering rock. In the tropics, many nests are also dug in the soil, but in moist forested areas, a common site is the soil beneath a rotting log or other large mass of rotting wood, with extensions of the nest into the log itself. Another frequent nesting site in tropical forest is in the humus and leaf litter at the base of large trees, particularly between buttress roots. Anochetus species of medium or small size often nest in small pieces of rotting wood or bark, or even small rotting twigs or seeds and nuts lying in or on the forest litter. Some species tend to choose more arboreal nest sites.

Diet. Foraging for living animal prey takes place on the soil surface, within the soil-humus-log mold matrix, or on the trunks, branches and foliage of trees and plants wherever these are available. Fragmentary evidence indicates that most epigaeically foraging tropical Anochetus tend to do their foraging at dusk, at night, or during dawn hours. I found Anochetus africanus walking on tree trunks only at night in the Ivory Coast. Some species, particularly those with red heads or other aposematic coloration, apparently forage in the open more during the day. No systematic comparative study has yet been made of foraging hours for different species.

The food of Anochetus consists principally of living arthropods caught and killed or incapacitated by the ants. The smaller and more delicate species Anochetus inermis has been observed by me in a laboratory nest. The colony came from a piece of rotten wood from the floor of a wet ravine near Bucay in western Ecuador. The colony was fed with small tenebrionid beetle larvae (Tribolium castaneum), comparable in size to the A. inermis workers, and the latter attacked the prey with their mandibles in the familiar snapping manner, but very cautiously and nervously, with stealthy approach, extremely rapid strike, and instant recoil-retreat. After several attacks of this kind, with intervening periods of waiting, during which the beetle larvae fled, rested, or writhed about in distress, an ant would finally attack with its mandibles and hold them closed on the prey for long enough to deliver a quick sting in the intersegmental membrane. After this, the prey appeared to be paralyzed, or at least subdued, and sooner or later was carried off by the ant to the nest, and eventually placed on an ant larva.

Frequent delays and excursions before the prey are finally immobilized and brought to the ant larvae in the nest may well have the function of allowing time for protective allomones of the prey to dissipate. Many tenebrionid adults, including Tribofium, possess potent quinonoid defensive allomones, but the larva is not known to possess quinones in this genus.

Nuptial flight. Although males of different species of Anochetus are commonly taken at light, other species are not. Stewart and Jarmila Peck gave me Malaise trap samples taken in western Ecuador that contained males of several species, but Malaise traps capture both day- and night-flying insects.

Defense. When a nest of any of the larger Anochetus species is breached, some of the workers immediately hide beneath leaves or other objects, while other workers rush about with open jaws, which they snap at foreign objects, or even at leaves and twigs, with an audible tick. On human skin or clothing, a worker will snap her jaws and hold fast to the surface with them, at the same time quickly bringing her gaster around to sting. The sting is long and strong, and to me the effect is shocking and quickly painful.

Most of the smaller and medium-sized Anochetus species feign death when disturbed, crouching flat against the surface, or rolling themselves into a ball and remaining still, often for a minute or more. Only when held do they sting. Their stings can be felt in most cases, but the effect is usually trifling.

Castes

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • bytinskii. Anochetus bytinskii Kugler, J. & Ionescu-Hirsch, 2007: 289 (w.q.m.) ISRAEL.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

TL 5.83–6.98, HL 1.42–1.61, HW 1.21–1.38, SL 1.22–1.41, EL 0.18–0.22, ML 0.75–0.87, AL 2.00–2.23, pNW 0.65–0.74, mNW 0.36–0.47, PL 0.34–0.42, PNH 0.26–0.36, GL 1.41–2.00, G2W 0.76–0.92, pTbL 0.96–1.13, CI 84.2–87.7, SI 97.5–105.7, EI 11.8–14.8, MI 50.3–56.8, PI 72.0–84.7, PNI 84.4–106.3, GI 93.9–100.0 (N = 46).

Head. Vertex deeply concave; shallow depression in front of rounded nuchal carina; median furrow absent, except smooth and shiny strip that enlarges in shallow depression at level of posterior margin of orbital fossa. Eye with 8–11 ommatidia across greatest diameter; ocelli absent. Scape slightly curved, barely reaching or slightly surpassing occipital lobe; funiculus 11-jointed, second segment L/W (length-width ratio) 1.9–2.3, about equal to third and fourth segments. Mandible slender, W/L 0.23– 0.27, broadened at distal half; medial edge with 2 nearly straight margins extending to semicircular preapical excision; ventral margin with series of 6–11 distinct, rounded denticles followed distally by 3–4 denticles fused into crenulated laminar process; denticles hidden from view by dorsal margin of mandible when head in “full-face” view and mandibles closed.

Mesosoma. Slender, pNW/AL 0.31–0.35, with well-marked pro-mesonotal and meso-metanotal sutures; pronotum sub-pyriform; mesonotal disk convex, wider than long, W/L 2.00–2.79; propodeal dorsum straight to slightly depressed transversely behind metanotal spiracle, narrow, smoothly rounded into declivity; no traces of propodeal angles or teeth; declivity slightly convex in transversal plane.

Petiole: distinctly longer than wide. Petiolar node triangular in lateral view, about as high as long, with rounded apex. In dorsal view, contour of base anteriorly ogival, posteriorly straight, with median concavity (posterior face flat, with feeble vertical sulcus); dorsal margin more or less compressed transversely – apex with distinctly transverse summit only in four of the largest specimens. In anterior view laterally arcuate with bluntly rounded apex.

Gaster. Sub-cylindrical, weakly constricted between first 2 segments; first gastric segment narrower than second in 39 out of 41 examined specimens, and about as broad as long.

Sculpture. Head punctulate, smooth and shiny except frontal striation; striae fine but distinct, medially 0.20–0.28 mm long; striae fan out posterolaterally, extending just posterior to frontal carina, and to level of posterior margin of compound eye, laterally entering antennal hollow but not exceeding posterior and lateral margins. Pronotum mostly smooth and shiny; cervix distinctly transversely striate with curved ruga, and posterior to ruga few fine, superficial striae arched parallel to margin; laterally smooth and shiny, finely punctuate; disc with scattered and coarse punctuation in 34 of 46 specimens, superficially and patchily rugo-striate toward margins in concentric pattern in other 12 specimens. Mesonotal disc crossed by up to 13 fine striae, although in 27 specimens anterior half more or less shagreened or striolate and strongly shiny. Dorsum of propodeum patchily rugo-striate and/or vermiculate on anterior third, posteriorly superficially cross-striate (11–16 striae per 0.2 mm); 2–11 striae present toward base of declivity; striae usually visible only in certain illumination, but in six specimens striation distinctly visible on propodeal dorsum and declivity, whereas in eight specimens striae too superficial to be counted; propodeum laterally with oblique striae. Mesopleuron and metapleuron smooth and shiny; ventral extremity of metapleuron with few oblique, strong rugae. Gaster and coxae smooth and shiny, sparsely punctulate. Antenna and mandible fine and densely punctulate.

Pilosity. Fine. Longest hairs (L 0.1 – 0.2 mm) abundant and decumbent on gaster, sparse and erect to suberect in bucal region and on coxae, absent on mesosoma, except one suberect hair on pronotal disk. Shorter hairs (L 0.04 – 0.10 mm) fairly abundant on head and thorax, sparse on propodeum and first gastric segment, obsolescent caudad; these hairs appressed to subappressed on most of head, pronotum and propodeum, erect on frontal carina, decumbent to erect on mesonotum, decumbent on gaster. Appendages covered by even shorter, appressed to decumbent pubescence. Propodeum nearly glabrous in few specimens.

Color. Living individuals yellow with orange tint. Dry specimens brownish yellow, lighter on mesosoma and coxae; gaster with brownish shading; epistoma, tip of mandible and leg brown.

Queen

TL 6.63, HL 1.37, HW 1.27, SL 1.22, EL 0.23, ML 0.71, AL 2.13, pNW 0.69, mNW 0.49, PL 0.41, PNH 0.35, GL 2.27, G2W 1.28, pTbL 0.97, CI 93.1, SI 96.1, EI 16.6, MI 52.2, PI 96.5, PNI 109.1, GI 96.9 (N = 1).

Dealate specimen, size (TL) of average workers, although with protibia length similar to that of smallest workers.

Head. Slightly shorter and markedly broader than in worker with similar tibia length. Eye with 13 ommatidia across greatest diameter; ocelli absent. Mandible as in worker, W/L 0.25.

Mesosoma. More robust than in worker, but with similar proportions; scutum W/L 1.32; scutellum hexagonal, with rounded edges, convex, L 0.19, W 0.27 mm; dorsellum elliptical, L 0.08, W 0.20 mm. Remnants of wings visible as dark brown stumps.

Petiole. Oval, broad, W 0.37 mm, only slightly longer than wide, node scale-like, more compressed fronto-caudally and higher relative to length than in workers.

Gaster. Longer and wider than in largest worker, sub-cylindrical, weakly constricted between first two segments, first tergite distinctly broader than long.

Sculpture. Head as in worker; pronotal and mesonotal disc and scutellum smooth and shiny. Propodeum laterally with oblique striae and coarse punctuation, declivity with 15 fine, transverse striae. Mesopleuron and metapleuron smooth and shiny. Gaster, coxae and head laterally shiny and sparsely punctulate.

Pilosity. More abundant on mesosoma, as compared to workers, most hairs decumbent to suberect; on gaster predominantly suberect pilosity in contrast to mainly decumbent pilosity of workers.

Color. Similar to workers.

Male

TL 4.17–5.02, HL 0.85–0.87, HW 0.98–1.00, ML 0.12, AL 2.05–2.09, EL 0.50–0.53, PNL 0.340.39, GL 1.97–2.35, fore wing L 4.11–4.19 (N=10).

Head. With large compound eyes; three ocelli, raised, shortest distance to compound eyes equal to four ocelli diameters, shortest distance to antennal sockets equal to three ocelli diameters; mandibles reduced, cuneiform. Scape about twice as long as wide, first funicular segment as long as wide.

Mesosoma. Robust, with convex dorsum and nearly straight pleura; propodeum convex, dorsum rounded into declivity.

Petiole. Node low, height about 0.5 of length, triangular in lateral view, apex bluntly rounded; dorsal margin shallowly concave in anterior view; anterior face flat; lateral margins almost straight and slightly convergent.

Gaster. Cylindrical, slightly constricted posterior to first segment. Terminalia partly retracted; pygidium broadly rounded; subgenital plate narrowed caudally into median digitiform process; cerci present; paramere broad, developed ventrally and apically into linguiform expansion.

Sculpture. Large, coarse punctures on head, mesosoma and gaster. Frons and mesosoma dorsum rugged, propodeum transversely rugulo-striate.

Pilosity. Body covered by dense, short, decumbent, golden pubescence, somewhat longer on gaster; antennae and legs with shorter, more abundant apressed to decumbent hairs.

Color. Body predominantly black, antenna and coxae dark brown, terminalia, tibiae and tarsi lighter brown to yellowish brown. Wings transparent with brownish tint, venation and stigma light brown.

Type Material

  • Holotype worker, ISRAEL: Migdal Aféq, 20.iv.1985, J. Kugler and D. Simon, No. 6484.
  • Paratypes: same collection data as holotype (17 workers, 10 males, emerged from cocoons in the laboratory, 4–31.v.1985); [Qiryat] Tiv’on, 11.vii.1989, J. Cnaani (2 workers); Elyaqim, Karmel, 23.iii.1989, J. Kugler (11 workers, 1 queen); Karmi’él, 18.ii.2005, Th. Assmann (5 workers); Oranim [near Qiryat Tiv’on], xi.1959, M. Costa (3 workers); Oranim, 19.iv.1972, J. Ofer (1 worker); Hirbet Usha, 2.vii.1985, D. Simon (11 workers). The holotype and paratypes are deposited in the entomological collection of Tel-Aviv University, Israel (Tel Aviv University Entomological Collection).
  • Paratype male from Migdal Aféq (as Migdal Zedek), 10 May 1985, J. Kulger (labeled as "Anochetus israelis Kulger") is housed in the Museum of Comparative Zoology.


Etymology

The new species is named after the late Prof. Hanan Bytinski-Salz, whose work on the ants of Israel inspired us. Prof. Bytinski-Saltz was the first to note the presence of this species among the Israeli fauna.

References