— — PROC. ENTOMOL. SOC. WASH. 105(1), 2003. pp. 186-194 A GREGARIOUS, MYCOPHAGOUS, MYRMECOPHILOUS MOTH, AMYDRIA ANCEPS WALSINGHAM (LEPIDOPTERA: ACROLOPHIDAE), LIVING IN ATTA MEXICANA (F. SMITH) (HYMENOPTERA: FORMICIDAE) SPENT FUNGAL CULTURE ACCUMULATIONS Sergio R. Sanchez-Pena, Don.ald R. Davis, and Ulrich G. Mueller (SRS-P. UGM) School of Biological Sciences. University of Texas. Austin. TX 78712, U.S.A.; (DRD) Department of Systematic Biology, Entomology Section, National Mu- seum of Natural History. Smithsonian Institution. Washington. DC 20560-0127. U.S.A. (e-mail: [email protected]) Abstract. —The lepidopteran Ainydria aiiccps Walsingham (Acrolophidae) is reported for the first time as a myrmecophile. Its gregarious larvae feed on the exhausted fungal substrate accumulations outside mature colonies of the Mexican leaf-cutting ant. Atta vie.xicana (Smith), a fungus-growing ant in Mexico. This constitutes the second report of an acrolophid myrmecophile. Morphology of the principal life stages of A. anceps are described, as well as its general natural history. No interactions were observed between Ainydria larvae and A. nie.xicaiui, although the larvae of A. anceps are attacked by ich- neumonid and tachinid parasitoids. Chalcids (primary or secondary parasitoids) also are associated with A. anceps larvae. Thus, there are potentially five trophic levels in this system: fresh plant material Atta fungal symbiont Aniydria anceps—ichneumonid and tachinid parasitoids—chalcid hypeiparasitoids. Kev Words: Acrolophidae. Aniydria. Atta. biology. Formicidae. leaf-cutting ant. Mexico, mycophagous, myrmecophile The attine leaf-cutting, fungus-growing strate consists mainly of fungal and plant ants, Atta and Acromyrmex spp., utilize cell walls and is disposed of by the ants. large amounts of plant biomass for the sub- The different species of attine fungus-grow- tenanean cultivation of the fungal symbi- ing ants show at least two strategies for dis- onts (Basidiomycetes: Agaricales: Lepiota- posal of the exhausted fungal substrate: ceae) they use as food (Waller and Moser some species (most Atta species, such as 1990, Mueller et al. 1998). The fungal Atta texana (Buckley) and A. cephalotes L.) strains cultivated by Atta and Acromyrmex create special subterranean galleries where have been identified as species of the mush- the used up fungal substrate is stored (Wal- room genus Leiicoagariciis. principally ler and Moser 1990); other species take this Leucoagariciis gongylophorus (Mciller), as substrate to the outside and dump it in well as similar species as L. weberi Mucho- "garbage piles" at variable distances from vej, Delia Lucia and Muchovej (Bononi et the nest. Species such as Atta mexicana al. 1981. Fisher et al. 1994. Pagnocca et al. (Smith), Trachymyrmex turrifex (Wheeler) 2001). After overgrowth by the fungus and (S. Sanchez-Pena, personal observation), subsequent harvesting of fungal biomass by and A. colonihica Guerin (Anderson and the ants, the manured, compostlike sub- Ratnieks 2000, Hart and Ratnieks 2001, U. VOLUME 105. NUMBER I Fiy. I. A mature colony of ,4/;(( iin-\iciiihi in the urban area ol Monterrey. Mexico. The substrate accu- mulalions on the .street by the curb (a) consist ol the spent lunyal material (dump.s) characteristic of this leaf- cutter ant. G. Miiellef. personal observation) fVeqiient- were collected at several localities in Mex- ly deposit tiie piles adjacent to the nest. The ico. During June and September 2(XX), gre- Ana substrate dumps, whether subterranean garious larvae of Aiuydria aiucps Wal- or exposed, constitute an accumulation of singham were discovered living in these ex- organic matter that attracts an abundant and ternal dumps in Monterrey, Santiago, and diverse community of invertebrates (Waller Guadalupe, in the State of Nuevo Leon, as and Moser 1990) and microorganisms well as in Queretaro, in the State of Que- (Rogers et al. 1995. Hart and Ratnieks retaro. Queretaro is approximately 800 km 2001, Sanchez-Pena, unpublished observa- from the other localities. Beutelspacher tions). (1977) previously had reared Aniydria an- Atra nu'xictinii (Smith), the Mexican leaf- ceps (which he redescribed as a new spe- cutting ant, is a widespread fungus-grower cies, Acrolophus socialis) without noting its in Mexico and parts of Central America. association with leaf cutting ants. Larvae of This species eliminates the exhausted, com- this species were reported by Beutelspacher postlike, fungal substrate by dumping it on as living in tubes within a compact mass or a garbage heap outside the nest (Fig. 1). "colony," resembling a termite nest. Beu- The exhausted fungal substrate is made up telspacher's specimens were collected at the of particles or granules up to a few milli- Estacidn de Bitilogia Chamela, Jalisco, meters in diameter. In both Attn coloinbica Mexico. and A. niexicana, these external dumps can Walter et al. ( 1938) reported another, but be more than two feet tall and have a vol- not congeneric acrolophid, "Ainyciha" coii- ume of several gallons. fiisella Dietz, from the subterranean cham- In May-September 2000, samples of as- bers where the Texas leaf-cutting ant, Atta sociated biota found on A. iiicxiciiiui dumps tcxuiui (Buckley), accumulates the spent PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON fungal substrate. This appears be the only- Thorax: Light brown dorsally and ventral- previous record of an acrolophid myrme- ly, heavily iiTorated with dark brown dor- cophile. Walter et al. (1^)38) collected lar- sally. Forewing length: d, 4.5-1 1.0 mm; 9, \ ae and adults from these subterranean 6.5-13.0 mm. Forewing light brown, vari- waste chambers. The utilization of the sub- ably irrorated with dark brown scales until teiranean chambers of .4. texcma (some of often appearing generally dark brown; a which are more than 2 m below ground sur- more or less distinct pattern of dark brown face) probably requires adaptations, behav- markings along costa, with largest forming iors, and cues different from those required an inegular, broadly U-shaped band from to exploit the exposed heaps of A. me.xi- basal third of costa to apical third: base of cana. The present deposition of Walter's wing with an oblique, dark basal band; an- specimens is unknown and, consequently, other large band extending Va-Vi across dis- the identification of the moth could not be tal 'A of wing; fringe light brown, irrorated verified. Larvae of both Amydria and Ptil- with dark brown. Hindwing uniformly light opsaltis. the allied genus which includes grayish brown to dark brown; 6 frenulum confuselki. are known to be scavengers on a simple, stout spine; 9 usually with 4 plant debris as well as guanophiles in caves smaller spines. Foreleg without epiphysis; (Davis 2000, Davis et al. 1986, Davis and light brown, heavily inxirated with dark Robinson 1998). brown over coxa and femur; tibia mostly dark brown with two light brown rings at AiiiyJrici cinccps Walsingham middle and apex; tarsomeres dark brown, with basal and apical light brown rings; Amydria anccps Walsingham Amydria aii- ceps Walsingham 1914: 363. — Davis midleg similar to foreleg in color; spurs light brown; hindleg uniformly light brown 1984: 20: 2000: 481. except for suffusion of darker scales dor- Acrolophus socialis Beutelspacher 1977: sally. Abdomen: Varying from uniformly 145. —Davis 1984: 20 (synonym o^ Amy- light in paler specimens to dark dria anceps). brown brown dorsally and light brown ventrally in Adult (Figs. 2-?).—Head: Pale buff darker forms. with darker brown scales concentrated near Male genitalia (Figs. 4-8): Uncus deep- vertex and lateral over occipital tufts, to al- ly bifid. Tegumen an elongate niinow dorsal most entirely dark brown. Vertex and oc- ring. Vinculum shoit, broadly U-shaped, cipital areas rough with semi-erect scales; with a slight median indentation (Fig. 4). frons usually less rough: scales slender with Gnathos fused apically into a nanow U- mostly bidentate, sometimes tridentate api- shaped sclerite. Vaha simple, nearly as ces. Antenna filiform, —0.4 length of fore- long as genital capsule, slender, tapering to wing: scape smooth, buff to dark brown: even more slender cucullus (Fig. 6). Ae- flagellum buff to brown, with a single an- doeagus —0.8 the length of valva. moder- nulus of slender scales per segment. Haus- ately broad and flat to apex; apical third lat- tellum and maxillary palpus vestigial, nor- erally separated into a larger, more mem- mally not visible on uncleared head. Labial branous dorsal half and a sclerotized. acute palpus slightly upcurved, with a strong ven- ventral half (Fig. 8); cornuti absent. tral scale brush, especially prominent on Female genitalia (Fig. 9): Posterior segment IL palpus buff, variably marked apophysis short, approximately as long as with dark brown, especially laterally; 2-3 the eighth abdominal segment. Lamella an- dark bristles arising laterally from 111, and tevaginalis — smoothly cur\ed. Ductus bur- up to 7 bristles from II; segment III elon- sae thickened, short, less than half the gate, slender, smooth, sometimes with a length of posterior apophysis, gradually en- dark median rins of dark brown scales. larging to mostly membranous corpus bur- VOLUME 105. NUMBER 1 ^:'^*^ '- , e^t . \ Fies. 2-3. Adults at' AniYclria , Male, forcwine Icti'jth S.."! mm. .^. Female, forewing leimlh II sae which extends about 3X length of along caudal half of corpus anterior to junc- apophysis; a small accessory bursa branch- tion of accessory bursa; anterior margin of ing off caudal end of corpus bursae at com- spinule patch deeply excavated. Ductus mon juncture with ductus bursae; basal, seminalis joined to corpus bursae from cau- ventral half of accessory bursae wall with dal end of cornutal excavatii>n. an elongate-oval ring of thickened tissue; Egg.—Upright, cylindrical, with IX lon- corpus bursae with an elongate, dense, gitudinal ridges evenly dispersed and con- coarse patch of small, irregularly shaped, verging toward either pole; length 0.46 mm, short spicules extending a short distance diameter 0.3 mm (Beuteispacher 1977).