Hatton, Gwladys N.

English

Journal of the Entomological Society of British Columbia

I·;';,),(L\IOLO(;H .\L SOl. OF BIUTIS H COIX3lHL\. PROl. (194i). VOl.. 44. FEll. 16, 1948 15 NOTES ON THE LIFE HISTORY OF SOME TABANID LARVAE (Diptera) i GWLA UYS N. HATTON Li vestoek Insects La bora tory, Ka mloops. B.C' . :\ consider;illle number of tabanid la rva e W l'l'C coll l'ctcd durin g Jun e and July in 1946 hI" th c staff of the D ominion Live-stock [I; sects Laboratorr, K amloops. l ' hese were kept a li ve in th e iaboratory hy differ-ent rcarill o· methods and detailed notes were ll1ad l~ Oil the feedin g hahits, Ilumhn of m olts, a lld th e acti vity, of' each indi-vidua l la rv a. [11 addition , a survey of In-ca I ponds W;IS made for ta banid egg masses :111<1 pupa l' . Til 19 :~4 , the late: I'vl r. Donald C am-nlln* rt' l'orted findin g f our tahanid larvae on th e marg: in of Moose L ake near K am-loops. Hc~ hpt them a live for several ll1onths, rem arking th at "they were ve ry r<:sistant to dry cOllditions and sometimes whell aPP;,rL·llt·ly dead and dried up, w ould iml11ediate ly become acti yc whcn m oisten-ed ;!!!ain". ]\; i nct'T n lar l'ae and one pupa wne col-lected on two trips to this lake in J un C' 1946, :lIld during successive trips to oth er like·l) pOllds around K amloops, a total of s ixtY-IIll l' lan·ac was f ound. Tabanid larva l' WLTC taken fr om Stake Lakc on th e Lac Ie J eun e road, Stra wberry H eig hts (Rayleig h, B.C.), ponds on thc hi ghway Ilear Sa voll a, ;Ind from a slough OIl the 1,<le dl! Bois ran ge . Pupa l' wtTe more difficult to find as thq Wcrl· II slially on th e surface o f th e ",round and well protec ted hy their brown l'(,lourin g . The first evidencc of pUp;t -tioJl was (Ill .Tune 15 , and during the IT -Illaind cr of JUll C and July, sevcn pupa l' we.re f ound- of w hich f our emerged. Thesl· were kindll" identifi ed hy Dr. C. B. Philip of th e Rocky M ounta in Laboratory, Hamilton , M ontana, ;tS Chr), sops furcatus Walk. '? , H.r bumitra sp. near hO(!lIIa-phor{/ M art. '?, Hr bomitra sp. it; , and Hybolll itl'rt i/!otllS, O. S., Co . 1 Contribution llio. 2514 . Di vision of Entomology. Science Ser vice 1 Departm e nt of Agri culture, Ott awa. Can ada . ., Forlll erly of the staff at th e Livestock Insec ts Lahoratory. K alflloops, B. C. The ideal shoreline for collectin g tab-anid l;tn·ae is a fairl y steep slope covered with m oss and loose black humus soil. Thcy a re probahly easier to find in a steep bank beca use of the concentration of lar-,·ae in a smaller arca dlle to the m oisture gradient. \.-loose Lake on th e Tranquill e range w here th e larvae were m ost easily f ound in June, is a small alga covered pond in the timher, bordered with tall grasses and damp m ossy humm oc ks. By sea rching ;: tea dil y through th e blac k mud with a trLwel a f ew inchc's from th e wa ter's edge, and parting th e clods of ea rth and rents with the hands, it was poss ibl e to find ahout three lan'ae an hour. Most of till'SC we re at a depth of fr om onc to th rce inch es, hut later on som e were found just tinder th e m oss on th e stlrface of th e mud and sC\l' ral la rge Ian ac: were taken fr om ,;<: 111 e' f a irly dry moss ;) foot abo,"c the watn . Th ere is slim e e\"idence th at th e lan·al· usua lly mO\ (' to a dryer a rca to pupate; this was aI , ,, nllted in th e I:tbora-tor). On July 12 a slough on the L ac dl! Bois range was found to providc a much ea ·:in co ll ec ting arc;\, Along th e shore lin C' a thick mat o f g rass ;tnd dehris had i' l· C' n was hed up, a nd hy turning this O\"cr, till" t:lhanid lanae cc uld be picked out ,,1-111"st at th e rate of on e a minute. Th t:· first lanat' c(l ll ected were main-tain ed in th e laboratury under th c follow-in g conditions: SO l11 l: in damp mild , some: in damp sa nd as recommcnded by I saac ( 1924), and others in la rge vials c onta in~ in!,!: hal f a n inch of wa ter and a short roll o f roug h paper towe lling, foll owing Philip's ( 1928 ) m odifi cation of M a r-chand 's technique. The first two m eth ods were discard ed for th e third, as the larvae ",caped repeatedly from the dishes o f lllud 'and sand. In the via ls the Jan-ae era wled between two laye rs of the paper and remained at the bottom completely 16 E~TU .\IO LUUI( .\ L SO('. OF BlnTl~lI COr.C.\IBL\ . PWJC. (1 947). VOl.. 44. F~;J:. 16, 1!J48 submerged III water with thei r respi ratory siphons extended to the surface . C ontinuing to lise Philip's method, the larvae were kept alive very successfull y by feeding them every two or three days on fly maggots and pieces of earthworm. Each larva was fed indi vidually between two pieces of damp towellin g on th e table top. It was necessa ry to keep them cov-ered while feeding as they arc thigmotro-pic and tend to re fuse f ood in order to crawl in search of cove r. N otes were kept on their feeding habits. When offered a piece of food they actually pounced on it, making a sharp clicking noise, and often th ey have heen observed to attac k one another in the same way when being fed. When collecting the larvae, each one waS placed in an individual vial since, if they were all together, several would be kill ed hy th e time they reached the lahor-a tory. The activity and amount eaten by each larva va ried considerah ly from day to da y. One large larva which had been inactive for a wee k escaped from a vial through two layers of cheese-cloth, and when discovered two days later, was ac-tively crawli ng along the hall two fli ghts of stairs below. Immediately before a molt they hecame very active and refused any food. In one instance a larva escaped through a cheese-cloth cover, continued through a water bath and ended up in the folds of a cardhoard box w here it was found the next day . H owever, although dried ollt, it was still alive, and ultimate-ly pupated. Three of the larvae fed in the labora-tory pupated and emerged. The pupal periods lasted nine, ten and thirteen days. In July and A.ug ust several lar/vae molted, hut none pupated. The maj ority remained active all winter, f eeding every f ew days OIl earth worms. Dr. Philip has determined these last cm crgcnces as: Chrysops furcatus Walk. ~ , H ybomitra sp., near sonomcnsis) Cjl, and Atylotus incisuralis Walk. Cjl. The first search for egg masses wa~ made on August 9 around the L ac du Bois slough and although th e larvae weI',' abundant a round the margin , no egg masses could be found. The wa ter plants forming a fri nge abou t four f eet wide arou nd the slough, and growing in black mud with water three to four inches deep, to a ll appea rances provided idea l oviposi-ti on si tes. A week la ter, after a very thorough search of this area , two egg masses we re found on the un de r an d upper sides of the leaves of the wa ter parsnip, seven inch es ahove th e water. T hev were both brown wi th a fl at surface and 0.7 cm . and 1. 5 cm. long in th e shape of a triangle. The eggs were laid in a si ng le laye r. Short pieces of plant hearing the eggs were placed in separate vials and kept on moss in a glass covered aquarium to keep them moist. Thirty larvae emerged from the la rge r egg mass six days a fter collec-ti on, and three days later, on A ugust 23, m in ute parasitic flies emerged from the remaining unhatched eggs. They contin-ued to emerge for the next four days and appeared to occupy the greater part of the egg mass. McQueen Lake on the same range proved to be a better collecting area, and in two trips there, thirteen egg masses were found on the tall sedges along the margin. These were of at least two species, as ten were shiny coal black, built up in a round-ed mass, three layers of eggs deep, and located on the under side of the blade. The other three were brown and deposited on the upper side of the blade with a fl at sloping surface to thei r triangular shaped mass, and no distinct layers 0 f eggs appar-ent. Larvae emerged .from two of these egg masses, but the remaining eleven were parasitized. The parasites w ere determined by Dr. C. F. W. Mueseheck of the United States N at ional Museum as Tclcttomus cmcr-soni (Girault). This species has been stated by Cameron (1926:38-39) to be a fairly common parasite of Chrysops mOt' -rens Walk. and Chrysops mitis O. S. in Saskatchewan. The newly hatched lan'ae fed well I';"TO'IOJ.O(;)C,\J. SOL OF BIO'rl SH COJ.l'\lIll.\, PIW('. (194 7), VOL. 44, FEB, 16, 1!J48 J7 whell placed on pieces o f earthworm. The midg ut showed red in th e almost trans-pa rent young larvae after they had fed, and (:' ven in these minute larvae th e black chitinous jaws were apparent. They were 'err resistant to dry conditions; a small lar va left ove rnight on some towelling re-\' i \'l'd w hen moistened with it I ittl e water. Howl'l'c r, no larvae hatched fr om egg masses were successfully rea red throug h to the adult stages . As the majority 0 f th e collected larvae ha \'l' heen f eeding all winter, it will be interesting to note whether this forced ac-tivit\ , in an)' way m odifies their deve lop-ment, since und er natural conditions they would remain dormant during the winter. ;\ill/ch yet remains to be learned ahout the early stages of many of our tabanid species, to say nothing of such mysteries as what happens to the minute adult parasi tes from one fall until the following mid-summer's egg supply, and further studies in this fi eld should hring to light interest-ing data. LITERATURE CrrED Cameron, A. E., 1926. Bionomics of the Tabanidae (Diptera) of the Canadian Prairie. Bul. Ent, Res. 17 (1) :1-42; plates 1-5; text-figs. 1-18. Isaac, P. V., 1924. Papers on Indian Tabanidae, Agr. Res, Inst., Pusa, India, Dept. Agr, Memoirs, Ent. series, Calcutta, 8:53-62. Philip, C. B., 1928. Methods of collecting and rearing the immature stages of Tabanidae (Diptera). Journ, P arasitol. 14 (4) :243-253; text-figs. a-b . SOME NOTES ON THE HABITS OF ARZAMA OBLIQUA ON VANCOUVER ISLAND. (Lepidoptera: Phalaenidae) RICH ARD Guppy Wellington, B.C. II r Zfl!llfl obLi'lUfl Walk. belongs to il group of Phalaenid moths which, though neither ahundant nor conspicllous, have a t-tracted a ttention because of the pec ulia r hahits () f the larvae. These mine in the stems of their food , plants instead o f feed-ing on the leaves in the ordinary mann er. 'rh e spec ies of the genus Ilrzfl ma are kn ow n hy the common nam e of " cattail moths" , from their usually recognized f ood plants, Typha fatif olia or related ''rattails''. Prof. ]. H. Comstock in his "Introduc-ti on to Entomology", g ives some data re-ga rdin g IIr-;:at//a obfi'lua which I reprod uce in part on account of its bearin g on my ohservations. "Two or more species of noc tuids in-fest the cat-tail plant, T ypha) in this coun-try. The larvae of both are at first lcaf-min ers, later they bore in the sta lks. Our most common species is II rZfl!llfl obLi'lUfl. According to the ohservations of Classen ( 192 1) the full-grown larva ove rwin-ters ill its burrow in the cat-tail plan t and transforms in the spring. But tbe la te Prof. D. S. K ellicott, who made a spec ial study of this species, informed me in a letter written in 1882, that the lana leaves the cat-tail plant in the fall and conceals itse lf under ba rk, in old wood and even in the g round until spring when it pupates, and em erges as a m oth in May. It is ('\'ident therefor e, that individuals of this species di ffer as to the location in which th ey pass the winter." I found these la n ae to be guite abund-ant in a low lying swampy area ncar my heme, whil e th ey were wintering under Jc.cse bark Oil fallen cedar logs . There arc Il o ca ttai ls anyw here in the vic inity; later I asce rtain ed the caterpillars were feedin g in the lea f stems of skunk cabhage ( Lvsichitoll kam tJchfltct?nse). I ha vc not heen successful in rearing the~ie Ian-ae from th e egg. Possibly it is necessary that the ova should be deposited on growing leaves o f the food plant. \Vhen taken from Lysichiton stems in late Aug ust of 1946 they were ('\'idently far past the leaf mining stage, thoug h still quite small. This however appears to ha\'e 

Notes on the life history of some tabanid larvae (Diptera)

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Notes on the life history of some tabanid larvae (Diptera)

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Journal of the Entomological Society of British Columbia