Temnothorax ansei

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Temnothorax ansei
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Temnothorax
Species group: laurae
Species: T. ansei
Binomial name
Temnothorax ansei
Catarineu, Barberá & Reyes-López, 2017

This species is known from two locations in southeast Spain: Pulpí (Almería) and Lorca (Murcia). It is distinctly nocturnal in its activity patterns.

Identification

Catarineu et al. (2017) - A member of the laurae group, by showing characteristic features of this group such as large eyes in relation to the length of the head capsule (OI > 30). Additional traits consistent with the laurae group are head capsule elongated (CI < 85), postpetiole more or less trapezoidal in dorsal view and widest anterior to the midlength of the segment (Prebus, 2015). As many species within this group, T. ansei is also found in arid environments.

Based on the morphology, the closest relative of T. ansei in the laurae group is Temnothorax universitatis. This other species is light brown or dirty yellow, with head less shiny, alitrunk dorsally opaque and pronotum laterally rugulose.

Other Iberian species in the laurae group are distinctive from T. ansei: Temnothorax blascoi is smaller, light yellow, with dense pilosity all over the body and with long and thin setae similar to Temnothorax recedens. Temnothorax caesari has mesosoma olivaceus brown, less shinning and less quadrangular head. Dorsal striae in pronotum and mesonotum. Pilosity erect on head and gaster. Temnothorax crepuscularis is yellow, with metanotal groove unmarked, abundant semi-erect setae on head and gaster, head and alitrunk rough, petiole and postpetiole dorsally rough. Temnothorax naeviventris is light yellow, with head and alitrunk coarse and opaque, and with pilosity erect in head.

Distribution

Distribution based on Regional Taxon Lists

Palaearctic Region: Iberian Peninsula, Spain (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Foraging workers of T. ansei were attracted to the baits at night, or sometimes during twilight (in June and July, the workers begin to forage from approximately about 19:00 GMT). After feeding for a few minutes, they carried a small cookie crumb to their nearby nest, although never more than one meter away. Through careful monitoring in a territory of about 230 m2, we were able to locate five nests, each with a single entrance hole in the soil of approximately 1 mm in diameter. These nests were very hard to detect as they lacked any external signs or evidence of ant activity.

We excavated the five nests and found that the main chamber was about 15-20 cm deep. Colonies ranged from two to 52 workers. Two of them had two wingless queens. Three of these colonies were relocated to our laboratory and have been maintained there under controlled conditions to date. The other two, an incipient colony with only two workers and other with 13, did not survive in captivity. Ants were fed with honey-water and small crickets and have produced during two years new males and females. These sexuals were born from eggs laid by the queen in the laboratory. All 19 queens born in captivity lost their wings in the first 1-4 weeks, 13 of them in the first three days, and then continued living normally in the nest, cooperating with the others. This behaviour has also been observed in other species of the group, for instance T. caesari (Espadaler, 1997b). Eggs, larvae and pupae were placed by the workers in one group on the floor of one chamber altogether.

Ecology

Both collecting localities are semiarid habitats with sparse vegetation cover, dominated by Stipa tenacissima L. grassland at the Pulpí site and chamaephytes and little shrubs at the Lorca site. Altitudes are 243 m at Pulpí and 464–591 m at Lorca. The average annual rainfall is 272 and 313 mm at Pulpí and Lorca sites, respectively.

We found 25 ant species at the same habitat, including T. universitatis, a species we consider, based on the morphology, to be the closest relative of T. ansei.

Reproduction

Queens are small and similar in size to the workers. Queen/worker volume has been related to nest founding strategies, independent or dependent (Stille, 1996). For T. ansei, this ratio is 1.91 (five workers and five queens from the same locality) and this fits with the dependent foundation (ratio 1.9–2.7), being very far from independent foundation range (ratio 5.1–9.1).

T. ansei queens were observed to lose their wings within the nest. Espadaler (1997b), studying T. caesari, found that seven out of seven queens born in the laboratory lost their wings within two days, and without being fertilized. It is known that the queens that disperse by mating flights do not lose their wings inside the colony (Hölldobler & Wilson, 1990; Heinze & Tsuji, 1995), and the rapid loss of wings in females seems to indicate intranidal mating (Heinze & Tsuji, 1995). Furthermore, T. ansei seems to be partially polygynous, both in the wild and in the laboratory. Two out of five nests excavated have had two wingless queens, and in the laboratory the three colonies nowadays have seven, six and two wingless queens respectively but this could be caused by laboratory conditions. Finally, we have found three worker-queen intermorphs (with our current data, the ratio intermorphs/workers is 3/32).

Our data suggests colony founding likely follows a Dependent Colony Foundation strategy.

Castes

Nomenclature

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

  • ansei. Temnothorax ansei Catarineu, Barberá & Reyes-López, 2017: 139 (w.q.m.) SPAIN.

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

Description

Worker

HL 0.66–0.76, HW 0.50– 0.59, CS 0.58–0.68, EL 0.16–0.24, WL 0.80–0.98, SPST 0.18–0.26, SPL 0.10–0.14, BI 1.60–2.50, TL 0.48–0.60; OI 29.55–44.19 (n=27 workers).

Head, mesosoma and gaster dark brown, mandibles, legs and antennae brownish yellow. Hairs on alitrunk, petiole and postpetiole long and erect (mean mesonotum hair length= 104μm). Mandibles, legs, funiculi and scapes with short decumbent pubescence. Head, pronotum and gaster with short and sparse decumbent pubescence. Head rectangular with parallel sides. Occiput straight. Eyes large (EL/CS=0.26-0.39). Antennae 12-segmented, antennal scape reaching occiput. Mandibles with five teeth: one apical longer, one subapical of intermediate length and the three smaller and irregular. Antennal club three-segmented, funiculus concolorous. Head smooth and shiny with some longitudinal costulae between the frontal carinae present, costulae never reaching occiput. Malar area costulate and reticulate. Clypeus smooth and shiny, a median longitudinal carinae, and two lateral carinae present and conspicuous. Frontal triangle smooth and shiny. Alitrunk with metanotal groove. Pronotum smooth and shiny. Mesonotum and propodeum laterally weakly reticulate, smooth and shiny dorsally. Propodeal spines long (SPST/CS=0.29–0.41), integument between spines smooth and shiny. Petiole and postpetiole finely reticulate-rugulose laterally, smooth and shiny dorsally. Petiole triangular in profile, with rounded apex and with four long setae on postero-dorsal surface. Postpetiole rounded in profile, trapezoidal in dorsal view, wider than long, and wider than petiole, with six long setae. Gaster smooth and shiny. Variability: propodeal spines can vary in size, apex of petiole varies from less to more rounded.

Queen

HL 0.66–0.71, HW 0.51– 0.58, CS 0.59–0.64, EL 0.19–0.24, WL 0.90–1.04, SPST0.19–0.25, SPL 0.09–0.14, BI 1.45–2.29, TL 0.50–0.59, OI 34.88–41.86 (n=8 queens).

Size and color as in workers. Hairs on alitrunk, petiole and postpetiole long and erect (mean mesonotum hair length=78μm). Eyes large (EL/CS=0.31–0.37), ocelli well developed. Antennae 12-segmented. Antennal scape reaching occiput. Antennal club three-segmented, funiculus concolorous. Mesosoma only slightly bigger than in workers. Anterior edges of pronotum slightly visible from the dorsal view. Pronotum, scutum and scutellum smooth and shiny. Mesopleurae with a few lateral costulae. Propodeum with lateral costulae, smooth and shiny between the spines. Petiolar node triangular in profile, its apex more acute than in workers. Well developed spines but somewhat smaller than in workers (SPST/CS=0.32–0.39). Petiole, postpetiole and gaster as in workers. Transparent wings, with very reduced veins. Pterostigma transparent, light yellow.

Variability: propodeal spines can vary in size, apex of petiole varies from less to more rounded.

Male

HL 0.49–0.58, HW 0.40– 0.50, CS 0.44–0.54, EL 0.19–0.23, WL 0.98–1.08, TL 0.60– 0.76, OI 45.00–50.00 (n= 5 males).

Head, alitrunk, petiole, postpetiole and gaster light brown; antennae and legs lighter. Hairs on alitrunk, petiole and postpetiole long and erect (mean mesonotum hair length = 84μm). Oval-shaped head, smooth and shiny. Very large eyes (EL/CS=0.42–0.46), nearly half of head length, located in the lower half of face sides. Ocelli well developed. Antennae 13-segmented. Scape surpassing the occipital margin and as long as the first 8 segments of the funiculus. Antennal club four-segmented. Mandibles with one apical tooth, one subapical and 2–3 smaller. Mesopleaurae and propodeum smooth, with less prominent costulae than in worker and queen. Pronotum, prescutum, scutum and scutellum smooth and shiny. Notauli marked. Scutum and scutellum separated by a depression. Metanotum present, narrow and separated from scutellum and propodeum. Propodeum reticulated, with some lateral costulae and without spines, only with a very slight angle. Petiole low and with node rounded. Gaster smooth and shiny. Wings as queens.

Variability: some males have the propodeum rounded.

Type Material

Holotype: a worker from a location nearby Pulpí (Almería, Spain), 1.716W, 37.389N (decimal format), Elevation 243 m, 23 July 2014, collected by C. Catarineu and labelled with the specimen code W01-10S501. Paratypes: 26 workers, 10 queens and nine males with the same data as holotype; six workers from Lorca (Murcia, Spain; three workers from 1.774W, 37.670N, Elevation 591 m; three workers from 1.774W, 37.685N, Elevation 464 m). All the paratypes were collected by C. Catarineu from July 2014 to June 2015.

The National Museum of Natural Sciences (MNCN, Madrid, Spain) holotype, two workers, one queen and one male (registration number C.T. 2730). The California Academy of Sciences, USA, two workers, one intermorph, one queen and one male (CASENT0763773, CASENT0763775, CASENT 0919826, CASENT0919953 and CASENT 0919954). The Natural History Museum, London, U.K., two workers, one queen and one male. Museum d’Histoire Naturelle, Genève, Switzerland, two workers, one queen and one male (MHNG ENTO numbers 10129 to 10132). University of Granada, Spain, two workers, one queen and one male. Coll. Xavier Espadaler (Autonomous University of Barcelona, Spain) two workers, one queen and one male. Coll. Joaquin L. Reyes-López (University of Cordoba, Spain) eight workers, three queens, one intermorph and one male. Coll. Chema Catarineu (Murcia, Spain) 11 workers, five queen, one intermorph and three male.

Etymology

The species recognizes and honours the Asociación de Naturalistas del Sureste (ANSE), an organization rooted in the south-east of Spain since 1973 (ANSE 2015). This is a naturalist and environmentalist, non-governmental organization which, by its efforts on nature research, awareness, and conservation activism, has earned the respect and support of generations of scientists and citizens. Most significantly, for the last five decades, ANSE has been a force of scientific and environmental activism promoting the formal recognition of the previously poorly-valued semiarid ecosystems of the south-east of Spain, where T. ansei, our newly discovered species, finds its home.

References