The Behavior and Life Histories of Two North American As~Alaphidsl'~
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The Behavior and Life Histories of Two North American As~alaphidsl'~ CHARLES S. HENRYS Department of Biology, Harvard University, Cambridge, MA 02138 ABSTRACT Life histories of the North American ascalaphids are given of several simple experiments on U.mexicana Ululodes nzexicana (McLachlan) and Ascaloptynx furci- assessing (1) the source and nature of the larval poison, ger (McLachlan) are described for the 1st time. Hatch- (2) the efficiency of food utilization by larvae, and (3) ing, growth and ecdysis, habitat preference, camouflage the role of the knobbed antennae in flight stability. Spe- and feeding habits of larvae of the 2 species are com- cial attention is drawn to the strong likelihood of terri- pared and contrasted. Data are also presented on cocoon toriality and aerial courtship and mating in Ululodes construction, pupation, adult eclosion, and adult feeding and other owlfly genera. An effort is made throughout and sexual behavior in U. mexicana, together with some the paper to place all data on U.lnexicana and A. furci- limited information comparing activity cycles and flight ger within the context of previously published observa- of the latter species with those of A. furciger. Results tions. It has been suggested that the ascalaphid adult was tal accounts or chance observations (e.g., Lafresnaye designed by committee. Antennae are long and 1846, or Eisner and Adams 1975). knobbed like those of a papilionoid lepidopteran. The Few larval studies of Ascalaphidae exist, and most eyes are large and spherical like those of an anisop- are based on forms that have not been reliably asso- teran, but are often divided by a deep sulcus in the ciated with adults : in fact, larvae of only 6 or possibly manner of some male mayflies. Wings are dragon- 7 of the 65 described owlfly genera can be identified fly-like in many species but in European genera are with confidence (Henry 1976). Works dealing with shaped and pigmented like those of butterflies. In larval morphology have been summarized (Henry body form, most ascalaphids are convergent on anis- 1976). Behavioral, physiological, and life cycle data opteran odonates but a number of tropical species on immatures usually appear as incidental comments mimic vespoid wasps (pers. observ.). They are com- in these morphological studies. More or less com- monly called owlflies, probably in honor of the fate of plete life histories exist for only 8 owlflies (7 are re- the minor Greek deity Ascalaphus: angry at his be- viewed by Balduf 1939). trayal of her daughter Persephone to Zeus' brother Ascalaphidae is a family of world wide distribution, Hades, Demeter transformed Ascalaphus into an owl most diverse in relatively dry and often mountainous by flinging water from the underworld river Phlege- habitats of the tropics and subtropics. The two sub- thon into his face (Tripp 1970, Zimmerman 1964). families of the taxon are well represented in the New The owlfly larva superficially resembles an antlion ; World, the Ascalaphinae or split-eyed forms by 4 indeed, myrmeleontids are close relatives of asca- closely related genera and the Keuroptynginae or laphids, but immatures of the two families may be entire-eyed forms by 6 less closely allied genera. The distinguished from one another and from other myr- ascalaphines Ululodes Currie and Colobopterus Ram- meleontoid larvae by a combination of morphological bur and the neuroptyngine Ascalaptynx Banks are the features (see Henry 1976). The pupa is of the dec- only owlfly genera common in the United States.' ticous exarate type and is formed within a cocoon Here I describe in some detail the life histories and constructed partly or wholly of silk. behavior of two sympatric ascalaphids from south- Literature on Ascalaphidae is strongly biased to- eastern Arizona, Ululodes wzexicana (LIcLachlan) ward taxonomic studies of adult forms. Even so, the and Ascaloptynx furciger (McLachlan), recon- classification of adults of the family is badly in need structed from field and laboratory observations. Since of review. On the one hand, evidence is accumulating the biology of the pre-larval and early hatchling that the morphological limits to species and even gen- stages of these species has been described in a pre- era are not nearly so well defined as was once thought vious paper (Henry 1972), emphasis will be placed (MacLeod4). On the other hand, forms of uncertain on post-eclosion larval instars, prepupal and pupal affinity are continually turning up in recent collections periods, and imago. The data are more complete for from the Old and New World Tropics. Basically, the U.mexicana and may readily be compared with those definitive monographs on the family (Weele 1908, from similar studies of other species of the genus NavCs 1913, 1914) are out of date. Biological infor- published by Guilding (1827), McClendon ( 1902) mation that might shed light on relationships among and NIacKeill (1962). A. furciger could not be in- adults is meagre, being confined primarily to anecdo- duced to enter pupation, so the present study is re- stricted to larval and free-living adult stages of this I Keuroptera: Ascalaphidae. species. 2 Received for publication July 19 1976. 3 present address: ~i~l~~i~~ls;iences G~~~~,vniversity of Wherever possible, I will correlate my observations Connecticut, Storrs 06268. 4 MacLeod E. G. 1964. A comparative morphological study j In at least one case, a species of Ulablodes has turned out of the head cHpsule and cervix of larval Xeuroptera (Insecta). to be the female of a Colobopterus species. (hlcLeod, pers. Ph.D. Thesis. Harvard Univ. Library, Cambridge, MA. 528 pp. comm.). 180 AXYALSOF THE ENTO~\IOLOGICALSOCIETY OF AMERICA [Vol. 70, no. 2 of the two Arizona species with those of other au- stored in separate 5 micropipettes. Head tissues thors on other owlflies. To my knowledge, however, were scooped out and emulsified using a small glass nothing has previously been published on the larval mortar and pestle. CALBIO plus PRONACE is a habits of C. wzexicana nor of any positively identified 1:l mixture of 2 enzymes prepared respectively by neuroptyngine ascalaphid. California Biochemical Company and Sigma Chemical Company, which digests a wide array of proteinace- METHODS AND MATERIALS ous substances. All solutions were stored at 4°C. The Methods and materials for finding, collecting, rear- effects of controlled quantities of each were assayed ing, preserving and dissecting ascalaphid eggs and on adults of Blattella gevwzanica (L.) by micro- larvae are dp~cribedin two previous papers (Henry syringe injection into the mesothoracic pleuron. Pro- 1972, 1976). Pupation of reared Clulodes larvae oc- cedure and results are summarized in Table 1 and curred in sand-filled petri dishes covered mith in- discussed in the text. verted 4-oz glass jars. Strips of paper toweling taped THE LARVA to the "roofs" of these jars permitted emergent pupae and imagoes to climb above the sand. Some adults Larvae of C.mexicavla have been reared from eggs were kept in cubic 30 cm wood-frame, nylon-mesh to adults and larvae of A, furciger from eggs to ma- cages. Others were placed in a large 5~3~2.8m ture third instars. I have obtained living specimens (LIVH) walk-in tent constructed of unbleached mus- of other species within the 2 genera in various stages lin covered with black plastic to prevent daylight from of development from Florida and Panama, but none affecting the light period within the chamber. h of these has been reared successfully. Additional data timer was connected to 280 \v of "daylight" fluores- on immatures of 1 or both of the 2 genera have been cent tubing suspended from the ceiling of the enclo- published by Guilding (1827), McClendon (1902), sure. Dead branches a meter or less in length were Peterson (1953), New (1971) and Henry (1972, lashed together and taped to the floor to simulate Ari- 1976). zona shrubbery. Three coverable clear plastic min- Eclosion and Early Larzlal Life.-Species of Ulz4- dows permitted observations to be made without en- lodes may be sympatric with those of Ascaloptynx, tering the tent. but larvae will usually be limited to different habitats Adult ascalaphids were fed Drosoplzzla melatzogas- based on divergent oviposition sites. In southeastern ter Meigen and D. hydei Sturtevant, which were Arizona, U.wzexicana chooses the hottest, most ex- either released live into one or the other of the cages posed canyon slopes with sandy or dusty surface soil or etherized and fed by hand to individual imagoes. for egg laying, while A. fztrciger oviposits in the par- Daily feedings were the rule. tial shade of scrub oak and juniper trees where dried Preliminary experiments to determine the source leaf litter accumulates (Henry 1972). Both species, and nature of the larval poison were conducted using as well as other known members of the 2 genera, lay mature U. men-icana 3rd instars. Various solutions their eggs on twigs; newly eclosed larvae remain on were prepared from the fluids and tissues of the larva the twig for up to 10 days. Llulodes larvae are pro- mixed with 0.01 M phosphate buffer, pH 6.8, as de- tected from predation during th~speriod by a rlng of tailed below : specialized abortive eggs or repagula placed basal to the egg mass by the parent, while the robust larvae Solution A (control) : pure 0.01 11 phosphate of Ascaloptytza acquire their first food from struc- buffer. turally less specialized abortive eggs. Wherever it has : 15-25% solution of jaw exudate and Solution B been looked for, active defense of the twig by newly buffer. hatched larvae of other ascalaphid genera has been 15-25% solution of head wound exu- Solution C: recorded (Westwood 1888, Froggatt 1900, Ghosh date and buffer.