Nymphister kronaueri

Nymphister kronaueri
Scientific classification
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N. kronaueri
Binomial name
Nymphister kronaueri
von Beeren & Tishechkin 2017

Nymphister kronaueri is a species of histerid beetle native to Costa Rica. It was first discovered in 2014.[1] The discovery of the beetle received much media attention due to its unusual habit of hitchhiking on army ants.[2][3] It was formally described in 2017.[4]

Discovery[edit]

The beetle was discovered by biologists Christoph von Beeren and Daniel Kronauer whilst investigating the relationships between army ants of the genus Eciton and their diverse fauna of symbionts in Costa Rica.[4][5] Alexey Tishechkin, together with Christoph von Beeren, named the new species after their colleague Daniel Kronauer, honoring his many discoveries in army ant research.[4]

Taxonomy[edit]

von Beeren and Tishechkin used DNA barcoding as well as the identification of morphological features to conclude that the new species is situated in the genus Nymphister, which previously contained only three other species N. monotonus, N. rettenmeyeri, and N. simplicissimus.[4] Nymphister is a genus in the histerid subfamily Haeteriinae, whose members are often associated with ants or termites.[6] These myrmecophiles or termitophiles often steal food from host colonies or even consume social insect brood.

Description[edit]

N. kronaueri is a small, dark red-brown beetle measuring 1.40-1.58 mm in length and 1.18-1.40 mm wide.[4]

Behaviour[edit]

Army ant Eciton mexicanum workers with N. kronaueri attached between the ants’ petiole and postpetiole.

N. kronaueri is noted for its unusual mechanism of phoretic transport - it uses its mouthparts (the mandibles) to attach itself to the waist (between the petiole and postpetiole) of medium sized ant workers of the species Eciton mexicanum. N. kronaueri was observed using this transport mechanism on different classes of worker ant when moving in a night-time emigration column; in almost all cases (>95%), specimens were found toward the end of this column where ant numbers were lower and no ant brood was being carried.[4]

Once attached, the beetles appear to mimic the ants' abdomens. To human eyes, this makes it appear that the ant has two abdominal segments, one above the other. However, given that their activities are largely nocturnal (they don't accompany the ants in daylight), it doesn't seem likely that the organism's nocturnal predators have forced N. kronaueri to look like part of a host's body as they do not hunt by sight. If morphological mimicry is a significant factor at all, it might rather be aimed at the ants themselves, helping N. kronaueri to conceal itself in the ant population (e.g., via Wasmannian/tactile mimicry). Besides the assumed morphological resemblance, the beetle mimics the chemical recognition cues of their host ants, thus smelling like an ant.[7] It has also been shown to be intensively licked/groomed by ant workers, indicating that it might additionally produce appeasing chemical compounds from exocrine glands.[7] Lastly, the beetle, like many members of the subfamily Haeteriinae, is able to retract all its extremities into preformed body cavities, leaving the ants no point of attack.[7]

Nymphister kronaueri has so far only been detected at a single site: La Selva Biological Station in Costa Rica, and has only been detected with the species Eciton mexicanum.[5] Given the cryptic habit and the relatively recent discovery, its actual distribution across the Neotropics will likely expand beyond Costa Rica.

References[edit]

  1. ^ "Beetles Pose as an Ant's Butt to Grab a Ride". Live Science. Retrieved 2017-02-17.
  2. ^ Yong, Ed (2017-02-14). "This Beetle Bites an Ant's Waist and Pretends to Be Its Butt". The Atlantic. Retrieved 2021-09-26.
  3. ^ Communications, ESF Office of. "Baffling Beetle | 2018 Top 10 Species | ESF Top 10 New Species". www.esf.edu. Retrieved 2021-09-26.
  4. ^ a b c d e f Christoph von Beeren; Alexey K. Tishechkin (2017). "Nymphister kronaueri von Beeren & Tishechkin sp. nov., an army ant-associated beetle species (Coleoptera: Histeridae: Haeteriinae) with an exceptional mechanism of phoresy". BMC Zoology. 2 (3). doi:10.1186/s40850-016-0010-x.
  5. ^ a b von Beeren, Christoph; Blüthgen, Nico; Hoenle, Philipp O.; Pohl, Sebastian; Brückner, Adrian; Tishechkin, Alexey K.; Maruyama, Munetoshi; Brown, Brian V.; Hash, John M.; Hall, W. E.; Kronauer, Daniel J. C. (2021). "A remarkable legion of guests: Diversity and host specificity of army ant symbionts". Molecular Ecology. 30 (20): 5229–5246. doi:10.1111/mec.16101. ISSN 1365-294X. PMID 34406688. S2CID 237199045.
  6. ^ Parker J. (2016). "Myrmecophily in beetles (Coleoptera): evolutionary patterns and biological mechanisms" (PDF). Myrmecological News. 22: 65–108.
  7. ^ a b c von Beeren, Christoph; Brückner, Adrian; Hoenle, Philipp O.; Ospina-Jara, Bryan; Kronauer, Daniel J. C.; Blüthgen, Nico (2021-09-19). "Multiple phenotypic traits as triggers of host attacks towards ant symbionts: body size, morphological gestalt, and chemical mimicry accuracy". Frontiers in Zoology. 18 (1): 46. doi:10.1186/s12983-021-00427-8. ISSN 1742-9994. PMC 8451089. PMID 34538256.