Life history, immature morphology and adult behavior ofTelenomus solitus [Hymenoptera: Scelionidae]

Abstract

The results of laboratory studies on the life history, morphology of immature stages, effects of food and water on adult longevity, host age preference for oviposition, parthenogenesis, and adult behavior of Telenomus solitus Johnson are presented. Telenomus solitus completed its development in 10.8 days (egg, 0.3 day ; I st instar, 2.7 days ; 2 *a instar, 3.7 days ; and pupa, 4.1 days). The adults lived longest when provided with both honey and water. Without food, they survived less than 24 h. Parasitization of host eggs varied significantly with their age, being highest in 42 h old eggs. Fewer than 10 % of eggs older than 60 h were parasitized successfully. The periodicity of oviposition was unimodal ; it occurred throughout the 24 h period and peaked in the late photophase. Females of T. solitus are arrhenotokous. The behavioral sequences during courtship, mating, and oviposition are described. KEY-WORDS:Telenomus, egg parasitoid, immature morphology, adult behavior.The Scelionidae is the largest family of Proctotrupoidea, with more than 70 genera distributed among 3 subfamilies and more than 20 tribes. Telenomus is a cosmopolitan, eurytopic genus, with more than 500 nominal species. Several species show some degree of specificity, primarily parasitizing only the eggs of host species from which they were reared (Anderson, 1976). Parasitization by a single species of Telenomus of insects in more than one order is uncommon (Johnson, 1984).In February, 1977, an undescribed Neotropical species of Telenomus was collected from eggs of an undetermined noctuid on potato foliage near Solola, Guatemala. This species was later described and named Telenomus solitus by Johnson (1983). We studied the biology of T. solitus Johnson before it was released for biological control. In this paper, we describe its life history and behavior. MATERIALS AND METHODS GENERAL EXPERIMENTAL PROCEDURESExcept for studies on the response of Telenomus solitus to varying temperatures, all experiments were conducted at 26.7 _+ 2 ~ 50 _+ 5 % RH, and 12L : 12D photoperiod (~) Current address : Southern Field Crap Insect Management Laboratory, P.O. Box 346, Stoneville, Mississippi 38776.

Efeito da estocagem em baixa temperatura na capacidade reprodutiva e longevidade de Trissolcus basalis (Wollaston) e Telenomus podisi Ashmead (Hymenoptera: Scelionidae)

“…A influência de baixas temperaturas na razão sexual dos descendentes foi também constatada em outras espécies de himenópteros parasitóides (Hanna 1935, Flanders 1938. A presença de exemplares do sexo feminino nas progênies oriundas de fêmeas estocadas a 15ºC, todavia, indica a ocorrência de cópula a 15ºC, uma vez que fêmeas virgens de Trissolcus e Telenomus produzem exclusivamente descendentes machos, apresentando portanto partenogênese do tipo arrenótoca (Noble 1937, Navasero & Oatman 1989, Loch & Walter 1999.…”

Effects of egg age of Spartocera dentiventris (Berg) (Hemiptera: Coreidae) on parasitism by Gryon gallardoi (Brethes) (Hymenoptera: Scelionidae)

“…According to Strand (1986) and Vinson (1998), hymenopteran parasitoids can parasitize and develop on all developmental stages of their hosts, being able to adapt to a range of host conditions. However, some stages, especially the younger ones, seem to be more appropriate to offspring development success, as demonstrated by a series of studies with scelionids, like Telenomus heliothidis Ashmed (Strand 1986); Telenomus solitus Johnson (Navasero & Oatman 1989), Telenomus remus Nixon (Hernández & Diaz 1996) and Tiphodytes gerriphagus Marchal (Souza & Spence 2001).…”

“…Female-biased sex ratios are common for many hymenopteran parasitoids species, including Scelionidae (Navasero & Oatman 1989, Noda & Hirose 1989, Hernández & Diaz 1996, Souza & Spence 2001, with these proportions explained in terms of local mate competition (LMC) (Hamilton 1967, Waage 1982. According to these authors, in parasitoids attacking gregarious hosts, as eggs in groups, mating generally occurs among siblings, with mother females adjusting offspring sex ratio so as to produce only a number of males minimally sufficient to guarantee mating for all offspring females.…”

“…Vinson (1997) states that there has been little interest on host age effects on parasitoid sex ratio, and so far little or no effect of host age on Scelionidae parasitoids (Navasero & Oatman 1989, Noda & Hirose 1989. However, a few authors as Hernández & Diaz (1996) verified a higher proportion of males of T. remus in older eggs of Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae).…”

“…Among these Gryon gallardoi (Brethes) has been referred as the main natural enemy of Spartocera dentiventris (Berg), the tobacco-grey-bug, in Rio Grande do Sul, Brazil, being responsible for a considerable mortality of the egg stage of this bug (Santos et al 2001). Studies with scelionids demonstrated that parasitoids are more successful in development when reared from younger hosts (Strand 1986, Navasero & Oatman 1989, Hernández & Diaz 1996, Souza & Spence 2001.…”