An experiment on colonization of karakurt (Latrodectus tredecimguttatus, Black Widow spider) on island territories in Kazakhstan

2 Pages·1993·0.5 MB·English

by  C K Tarabaev

AN EXPERIMENTON COLONIZATION OF KARAKURT
(LATRODECTUSTREDECIMGUTTATUS, BLACK WIDOW SPIDER)
ON ISLANDTERRITORIES IN KAZAKHSTAN
CHINGIS K. TARABAEV
Tarabaev, C.K. 1993 11 11: An experiment on colonization of karakurt (Latrodectus
tredecimguttatus, BlackWidow spider)on islandterritoriesin Kazakhstan. Memoirsofthe
QueenslandMuseum33(2): 651-652. Brisbane. ISSN0079-8835.
To create an artificial, controllable population ofLatrodectustredecimguttatus (karakurt)
withtheaimofcollectingvenom,anexperimentonmasscolonisationofsouthernpopulation
spidersonanislandterritory wascarriedout. Retardation oftheoverwintering stageunder
laboratory conditionsensuredtheavailability oflargenumbersofkarakurtforcolonisation
andeliminateditsuncontrollablereproductioninneighbouringterritories.
Pour creer une population artificiele bien controlee des Latrodectus tredecimguttatus
(karakurt) dans Ie but d'obtenirdu venin on a mis une experience de la dissemination des
Araigneesdelapopulationm£ridionalesurleterriloireinsulairs.Ledelaidustadehivernant
dans les conditions de laboratoire assure la stabilisation du nombre de masse de karakurt
pourleurcolonisationetelimineleurreproductionnon-controleesurleslerritoiresadjacents.
\Z\Colonisation, karakurt, eggsacs, Latrodectus,
Chingis K. Tarabaev, Institute ofZoology ofKazakhstan NationalAcademy ofSciences,
Akademgorodok, 480032Alma-Ata, Kazakhstan Republic; 19March, 1993.
In Kazakhstan, mass annual collections of anumerous,yetcontrollablekarakurtpopulation.
venom-producing arachnids are carried out to Todosoweretardedthedevelopmentofspiderl-
obtain their venom for medicinal and other pur- ings and then released the 2nd instars over the
poses. Black widow spiders ("karakurt*, island. As a result, the spiderlings avoid the dis-
Latrodectustredecimguttatus(Rossi))arecaught astrouslatefrostsbutthepostembryosofthenew
in the greatest numbers. At the same time, their generation in theiregg sacs would nothavetime
abundance varies from year to year: quite often to develop into overwintering 1st instar spiderl-
periodsoccurduringwhichonecanhardly finda ings.Thisphenomenonisthereforethenecessary
single specimen (see Marikovskij, 1956; Levi, conditionforthepossibilityofcreatingacontrol-
1983;Tarabajev, 1990). Abitefromakarakurtis lable karakurtpopulation, as well as forelimina-
an appreciable danger. Hence, during periods of tion of uncontrollable mass reproduction of
greatabundance,itmustbecontrolled.Inconnec- spiders on the neighbouring territories. For the
tion with this problem, we carried out an experi- intensification of degree-days deficit effect, the
ment on karakurt colonisation on an island with spiderlings from 500 egg sacs of Latrodectus
the aim ofcreating an abundant and controllable tredecimguttatus collected in Uzbekistan
artificial population. (southernpopulation fromDzhizakSteppe)were
used in our experiment. Before the colonisation
MATERIALS ANDMETHODS we made a census of the native population of
karakurt on the island.
The experiment was performed on the small During winter,eggsacsofsouthernpopulation
island 'Malyj' (1.4km) in Alakol' Lake spiderswithoverwinteringfirstinstarspiderlings
(46°08*N, 81°52'E) near the northern border of were kept in the laboratory (temperature 0-5°C).
the known karakurt distribution: the 2nd instar In the second halfofMay these wereplaced into
spiderlings emerging from egg sacs are often a gauze-covered 20 litre vessel atroom tempera-
affected here by the late frosts which occur in ture (18-22°C), fortheirreactivation fromwinter
April-May (Tarabajev, 1990). In contrast, the diapause. Aftermoulting in theiregg sacs, many
development ofspiders is critically restricted by spiderlings emerged; then the vessel which con-
the shortened warm season: if the postembryos tained them was placed in a refrigerator (4-5°C)
within the egg sacs have no time to develop into until June.
the overwintering 1st instarspiderlings, they die Before mass colonisation, a census of the
during winter (Marikovskij, 1956). This naturalkarakurtpopulationon 'Malyj' Islandwas
phenomenonstipulatedthepossibilityofcreating carried out by the visual investigation of the
652 MEMOIRS OFTHEQUEENSLANDMUSEUM
whole island territory fii for the settling by the In August-September, mass collection of
southernpopulationspidersofkarakurt(ca. 8500 females must be carried out. These females are
m2). kept in collection boxes for 2-3 weeks until they
lay their egg sacs in these boxes. (This
RESULTS phenomenon wasfirstnoticed by us when study-
ing the technique of mass collecting from the
While making a census ofthe native karakurt field). Females are subsequently used forobtain-
population on 'MaJyj' Island before mass ing venom while egg sacs are kept at room
colonisation on 12 June 1988, wefoundone nesi temperature until the 1st instar spiderlings
from the previous yearwith twoempty egg sacs, emerge (overwintering stage). After that the egg
and two more old nests. Six living karakurt sacs must be kept in a refrigeratorat 0-5°C until
specimensof4-5thinstarwerealsofound-Bylate the following season.
August there were 3726 nests from the southern After tbe reactivation of spiderlings in spring,
population, or one specimen per 2-3in * Three they are released over the island, which they
females of the native karakurt population were recolonised effectively. Every August-Septem-
also found: they differed by their larger si/e (no ber, masscollectionoffemalesiscarriedout,and
females were measured). In 28 nests ofsouthern the cycle is renewed.
populationspiderstherewasonlyoneeggsacper Thus, theindubitable advantageofour method
nest: noegg sacs were found in the rest, while in is the elimination of uncontrollable mass
three nests of native population spiders there reproduction ofkarakurt and the absence of any
weretwoeggsacsineach. Dissection ofeggSacs necessity of special egg sacs collecting for
confirmed our views. In four egg sacs of the colonisation.
native karakurt population there were pos-
tembryos, in two there were first instar spiderl- LITERATURECITED
ings, while only eggs were found in 20 egg sacs
ofOtfhe1s0o0utnheesrtsn epoxpaumliantieodn.in May 1989, 74 nests LEVI,anHd.Wc.ol1or9a8t3i.onOninthseepvaarlauteinogfgsepneictiaelisaosftrwucitduroews
were without egg sacs-some ncsls were ruined; spiders {Lalrodectus sp.) (Arachnida: Araneae:
26nestseachhadoneeggsac,alleggsweredead. Theridiidae). Verhandlungen des Naturwis-
Theseresultsconfirmedthatduetotheartificially senschaflliehen Vereins zu Hamburg (NF) 26:
retarded development of southern population 195-200.
spidersinthenorthernconditionsofAlakoF Lake MARIKOVSKU, P.I. 1956. [Tarantula and karakurt:
theeggs haddied within the eggsacs as they had morphology, biology, toxicity]. (Kirghiz SSR
insufficient time to develop to theoverwintering Academy of Sciences Publishers: Frunze.), [in
Russian]
tfiermstpeirnasttaurrespiindeSrleipntgesm(btehre aisvenroagmeoArleaktohla'nar1e0a- TARAaBsAtJheEVre,asCoHn.of19k9a0r.akWuirntte(rBlHaocsktsWainddolwateSpfirdoesrt,s
I5°Q.
Wethereforepropose the followingschemefor LKaaztawkdhesvttaun.s BturltldeteicnimdgeualaatuSso)ciedteeprEeusrsoipoenennien
thecreation ofmany controllable artificial black d Araehnologie (ComptcsRendusduXII Col-
widow populations for the purpose of obtaining loque Europeen d'ArachnoIogie. Paris (France).
venom. 2-4juillel 1990), No. hors serie 1: 346- 348.