64 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY POPULATION BIOLOGY AND ADULT BEHAVIOR OF LYCAENA AROTA (LYCAENIDAE) JAMES A. SCOTT 60 Estes Street, Lakewood, Colorado 80226 The purpose of this paper is to describe adult behavior (mate­ locating, mating, feeding, oviposition, and basking), dispersal, and pOpu­ lation parameters (especially lifespan) of L. arota Boisduval. A mark-recapture study was conducted in 1969 at the mouth of Rouch Gulch (Spring Creek), Fremont County, Colorado. L. arota was also studied in 1971 one km east of Smith Creek Campground, Custer County, Colorado, and at Little Fountain Creek, EI Paso County, Colorado. These sites were mountain gulches or streams with abundant larval host, Ribes spp. METHODS Number of matings per female was determined by counting spermato­ phores (Burns, 1968). For study of movements and estimation of popu­ lation parameters, butterflies were marked individually using the method of Ehrlich & Davidson (1960). They were captured with a net, marked, and immediately released at the site of capture. Analysis of population movements. The following method allows direct comparison between the sexes and between species, determination of change of movements with age, and separation of the velocity and distance aspects of movements. On a map of the movements of each recaptured individual, distances in mm between each two captures are measured, and called d1 between first and second captures, d 2 between second and third, etc. Total distance moved by the individual, D, is the sum of the d's. Range, R, an estimate of dispersal, is distance between the two most distant capture points. Time in days between first and second capture is called t1, etc. T is total time between first and last capture. Velocities are defined Vi = d;/ti and V = D/T. Midpoint age between captures is determined by finding the age midway between two captures after calling the first capture day O. Correlations between distance or velocity and midpoint age determine whether movements change with age. Midpoint age is used rather than age at start or end of a period between captures because the time between captures differs. Jolly's stochastic method was used to estimate population size, survival rates, and number of new individuals joining the population (Jolly, 1966). The method of Cook et al. (1967) was used to obtain expected lifespan from average survival rate. VOLUME 28, NUMBER 1 65 RESULTS Mate-locating behavior. To locate females, males perch on branches of shrubs and trees 1 to 2 m above the ground. Males start perching at about 0715 and actively perch until noo. Males gradually stop perching between noo and 1200, and rarely perch after 1200. In the afternoon, males mainly visit flowers, or are quiescent on shrubs. Perching males sit on a branch or leaf and dart out at passing objects. Most such objects are other males, whereupon the two males fly about each other for a few seconds, then each returns to or near the same perch as before. One male was observed to perch on a one-meter length of oak branch for two hours dming which time he made almost 100 short flights at passing objects. Other males sometimes flew short distances between investigative flights. Males chase a narrow size range of passing objects, so that almost all of the chases are toward other L. arota. Males perch in small clearings in many different topographic situations. A clearing likely to have perching males is about 3-5 m. in diameter, rea­ sonably level, and surrounded by tall trees or steep hills or both. Males were observed to perch in clealings that were in a small valley bottom, on a hillside along an irrigation ditch, and on a ridgetop. More males perch in valleys than hillsides or hilltops because more suitable clear­ ings are found there and the larval hostplant is usually more abundant there. Mating. If a female flies past a perched male, the male darts after her and flies about 14 cm below her for several meters, then the female lands on a branch and the male lands behind. The male then usually flicks his wings by holding them about 60° from the vertical (about 120° from each other) and vibrating them at small amplitude (only 1-2 mm amplitude for each wing). Sometimes the male vibrates the wings only once or twice per second, and other times he vibrates his wings rapidly (about 10 times per second), occasionally with the vibrations clustered into groups. These two types of wing flicking occurred about equally often, but only one type was seen in anyone courtship, except for one courtship in which the male vibrated his wings once per second, then drew closer to the female and vibrated his wings about 10 times per second. Other males did not flick their wings at all, but merely walked to the female and attempted copulation. \Vhether or not the male flicks his wings, if the female remains quiescent the male crawls along­ side and bends his abdomen either right or left to attempt copulation. In the two completed copulations observed, the female was quiescent during courtship and mating. Unreceptive females flap the wings almost full stroke about 10 or more times per second for about 2-5 seconds, while 66 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY TABLE 1. Dispersal data for Lycaena arata. N = sample size. Dispersal param­ eters are defined in methods section. Dispersal Parameter Males N Females N Number Marked 107 94 Number Recaptured 53 37 Average T (days) 2.56 53 1.91 37 Average t. (days) .94 144 .84 85 Average R (meters) 15 53 29 37 Average D (meters) 16 53 29 37 Average d, (meters) 6 144 13 85 Average V (meters per day) 11 53 18 37 Average Vi (meters per day) 5 144 9 85 sitting. In most courtships the female was previously mated, and she performed this "rejection dance" when the male crawled up to her; the male flew away then or after subsequent rejection dances. Male wing flicking may cause the female to become quiescent and receptive, because if the female is already quiescent, the male usually does not flick his wings. Courtship and mating occur at the same time as male perching. Copulating pairs were found at 0805, 0920, 1121 and 1200, all in valley bottoms by Scott, and at 0930 and 1326 (Oakley Shields, pers. comm.). 1326 is after the normal perching period, and that observation may represent the mating of a late perching male, or perhaps the mating was initiated during the normal perching period and the pair remained joined until observed (copulation of butterflies lasts rarely up to 30 hours). Nineteen courtships were observed from 0815 to 1036, and one was observed at 1121. Females rarely mate more than once. Of 60 females dissected (caught several weeks after the species had first appeared), 15 were virgin, 44 had mated once, and only 1 had mated twice. Many virgin females were found in the afternoon, indicating that many females wait until the day after emergence to mate. Movements. The mark-recapture study was carried out from 30 July to 8 August 1969. Rouch Gulch is a small, dry (except after rains) gulch opening into the Arkansas River, within the pinyon-juniper belt. The larval host, Ribes leptanthum, and adult nectar sources were scattered along the bottom, where the recapture study was carried out from the Arkansas River to 300 m. up the gulch. Nearby gulches were sampled to detect dispersal. The proportion of recapture (Table 1) was higher for males, probably because males disperse less than females. Although TABLE 2. Population parameters estimated from multiple recapture data using the stochastic model of Jolly (1966). Alpha-pro- -<0 portion of marked animals; M-total marked population; N-total population; Phi-probability of survival; B-number of new animals t"' joining the population; SE-standard error. C ~ ~ Day Alpha M N + 1.96 SE Phi + 1.96 SE B + 1.96 SE to vCXJ Males Z July 30 .959 + .394 c ~ 31 .2581 43.13 167.1 + 112.9 .662 + .275 13.1 + 69.4 IJl ~ Augllst 1 .3538 1,.3.77 123.7 + 45.4 .997 + .758 91.6 + 90.2 i:C ...... 2 .3836 80.50 ~09.9 + 164.6 .164 + .159 68.7 + 46.4 5 .1406 13.50 96.0 + 53.5 .593 + .548 47.7 + 63.0 6 .1111 8.00 72.0 + 70.4 7-8 .1818 Females July 31 .374 + .242 August 1 .0833 14.23 170.7 + 160.8 1.076 + .767 79.8 + 187.8 2 .2283 59.40 260.2 + 200.6 5,6,7 .1000 Both Sexes Combined July 30 1.157 + .476 31 .1304 57.87 443.7 + 311.1 .489 + .177 24.3 + 146.6 August 1 .2389 57.62 241.2 + 82.8 1.022 + .528 228.4 + 160.7 2 .2970 138.56 466.6 + 253.5 .264 + .224 209.0 + 178.3 5 .1311 40.00 305.0 + 228.4 .438 + .514 105.4 + 155.4 6 .0909 17.50 192.5 + 205.6 7-8 .1087 0:> -1 68 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY TABLE 3. Flowers and other fluid sources visited by L. arota at the three study sites. Rouch Little Gulch Smith Fountain Creek Species Color Creek Male Female Cmpgd. Solidago occidentalis yellow few 236 158 Pericome caudata yellow 52 75 Eriogonum iamesi whitish -yellow few 30 64 Heterotheca villosa yellow 5 9 Chrysothamnus naltseOSllS yellow 6 5 H elianthus pumilus yellow 2 2 Allium sp. white 1 Rubus parviflorus'- 5 3 mud 1 Rudbeckia laciniata yellow many M elilotus alba white many Aster novae-angliae bluish white many Apocynum sp.