TY - JOUR

T1 - Hairs distinguish castes and sexes

T2 - identifying the early ontogenetic building blocks of a fungus-farming superorganism (Hymenoptera: Formicidae)

AU - Adams, Rachelle M. M.

AU - Larsen, Rasmus S.

AU - Stylianidi, Nicoletta

AU - Cheung, Dave

AU - Qiu, Bitao

AU - Murray, Stephanie K.

AU - Zhang, Guojie

AU - Boomsma, Jacobus J.

PY - 2021

Y1 - 2021

N2 - Ants are among the best-known insects, but the morphology and development of their larvae are rarely studied in a systematic manner. Precise information on larval development is needed not only to understand ontogenetic development of caste phenotypes but also ultimately to allow a better understanding of the integrated development of entire ant colonies - superorganisms that have an inseminated founding queen as germ-line, cohorts of unmated workers as soma, and the iteroparously produced gyne and male reproductives as gamete analogues. Here, we present a survey of larval morphology of the fungus-growing ant Acromyrmex echinatior (FOREL, 1899), documenting the four instars of large and small workers and the five instars of gyne and male larvae. We used a combination of quantitative traits (body length, body curvature, hair patterning, head to body length ratio) and binary traits (presence / absence of anchor-tipped hairs, gut full / empty, head moving or not), and we document variation across the instars and sexes for 251 individuals with z-stacked images. Based on the statistical resolution of single and combined traits, we provide a key for the 3rd to 5th instar larvae, where sex and developmental stage can be unambiguously identified, and offer notes on the second instar, where identifications are statistically possible but with lower accuracy. This key is also available as an electronic resource . We discuss the challenges involved in this type of research and highlight opportunities for addressing new research questions that become accessible when sex-specific and caste-specific larval instars can be distinguished.

AB - Ants are among the best-known insects, but the morphology and development of their larvae are rarely studied in a systematic manner. Precise information on larval development is needed not only to understand ontogenetic development of caste phenotypes but also ultimately to allow a better understanding of the integrated development of entire ant colonies - superorganisms that have an inseminated founding queen as germ-line, cohorts of unmated workers as soma, and the iteroparously produced gyne and male reproductives as gamete analogues. Here, we present a survey of larval morphology of the fungus-growing ant Acromyrmex echinatior (FOREL, 1899), documenting the four instars of large and small workers and the five instars of gyne and male larvae. We used a combination of quantitative traits (body length, body curvature, hair patterning, head to body length ratio) and binary traits (presence / absence of anchor-tipped hairs, gut full / empty, head moving or not), and we document variation across the instars and sexes for 251 individuals with z-stacked images. Based on the statistical resolution of single and combined traits, we provide a key for the 3rd to 5th instar larvae, where sex and developmental stage can be unambiguously identified, and offer notes on the second instar, where identifications are statistically possible but with lower accuracy. This key is also available as an electronic resource . We discuss the challenges involved in this type of research and highlight opportunities for addressing new research questions that become accessible when sex-specific and caste-specific larval instars can be distinguished.

KW - Acromyrmex echinatior

KW - leaf-cutting ants

KW - larval development

KW - z-stack

KW - taxonomy

KW - ANT ACROMYRMEX-ECHINATIOR

KW - CONFLICT

KW - WORKER

KW - LARVAE

KW - BROOD

KW - EVOLUTION

KW - DIFFERENTIATION

KW - REPRODUCTION

KW - POLYMORPHISM

KW - RECOGNITION

U2 - 10.25849/myrmecol.news_031:201

DO - 10.25849/myrmecol.news_031:201

M3 - Journal article

VL - 31

SP - 201

EP - 216

JO - Myrmecological News

JF - Myrmecological News

SN - 1994-4136

ER -