Reproductive Responses to Photoperiod by a South Florida Population of the Grasshopper<i>Romalea microptera</i>(Orthoptera: Romaleidae)

Luker, L; Hatle, John D.; Juliano, Steven A.

doi:10.1603/0046-225x-31.4.702

Cited by 20 publications

(31 citation statements)

References 25 publications

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“…Tanaka et al, 1993;Kawano & Ando, 1997), although it is certainly not a general rule (Hodek, 1979;Ando, 1991;Ruberson et al, 1991;Canard et al, 1994;Kawano & Ando, 1997;Musolin & Saulich, 1999, 2000Inoue, 2001;Luker et al, 2002;Tommasini & Van Lenteren, 2003). However, a comparative study of several Trichogramma species from various climatic zones is needed to test this hypothesis.…”

Section: Discussionmentioning

confidence: 99%

Effect of photoperiod on parasitization by Trichogramma principium (Hymenoptera: Trichogrammatidae)

Reznik¹,

Vaghina²

2007

Eur. J. Entomol.

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Abstract. The effect of photoperiod on parasitization of the eggs of the Angoumois grain moth, Sitotroga cerealella (Olivier, 1789) by Trichogramma principium Sugonyaev & Sorokina, 1976 was investigated under several photoperiodic regimes of L : D = 3 : 21, 6 : 18, 9 : 15, 12 : 12, 15 : 9, 18 : 6 and 21 : 3. In all regimes, certain wasps delayed ovipositing in this non-preferred host. Potential fecundity of T. principium females (the number of mature ovarial eggs at emergence) and subsequent oogenesis (estimated by the number of mature ovarial eggs in non-ovipositing females) was independent of photoperiod. However, the percentage of females that oviposited was higher for females that developed and were kept under 6-12 h long photophase than for those that developed and were kept under ultra short (3L : 21D) and under long (18L : 6D and 21L : 3D) photophases. The average duration of the preoviposition (egg retention) period showed the opposite pattern to the photoperiodic response. A possible explanation of this reaction is that the delay in oviposition is adaptive if the probability of finding a better host is high. In autumn, when the last Trichogramma females are still active but their lepidopteran hosts are already much less abundant, then parasitization of any suitable host is the best strategy.

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Section: Discussionmentioning

confidence: 99%

Effect of photoperiod on parasitization by Trichogramma principium (Hymenoptera: Trichogrammatidae)

Reznik¹,

Vaghina²

2007

Eur. J. Entomol.

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“…Analisando o efeito do fotoperíodo sobre a reprodução em insetos, Tanaka et al (1993), Tanaka & Sodoyama (1997) e Ekesi et al(1999) observaram que gafanhotos Megalurothrips sjostedti (Tryborn), Nomadacris succincta L. e Locusta migratória L. quando submetidos a fotoperíodo curto apresentaram redução na produção de ovos e realizaram Luker et al (2002), analisando a resposta reprodutiva em populações de gafanhotos Romalea microptera Beavois (Orthoptera: Romaleidae), verificaram que fotoperíodos curto (11,5L/12,5E) e longo (13,75L/10,25E) não interferiram no período de oviposição, número de ovos e média de massa seca de ovos. Porém, esses autores observaram ainda que a associação do curto fotoperíodo com redução da alimentação produziu alterações nos parâmetros estudados.…”

Section: Discussionunclassified

Ultra-estrutura dos ovaríolos de Tropidacris collaris (Stoll) (Orthoptera: Romaleidae) submetido a três fotoperíodos

Santos¹,

Veiga²,

Santos³

et al. 2007

Neotrop. entomol.

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Ultrastructure of the Ovarioles of Tropidacris collaris (Stoll) (Orthoptera: Romaleidae) Submitted to Three Photoperiods ABSTRACT -The research evaluated the ultrastructure of the ovarioles of Tropidacris collaris (Stoll), submitted to photoperiods 10L:14D, 12L:12D and 14L:10D. Sixty nymphs (30 males and 30 females) in the last stage of development were paired in ten couples in each treatment. Thirty days after adult emergence, the females were immobilized with ethylic ether and dissected under stereomicroscope. The ovarioles were transferred to Karnovsky fixative (2.5% glutaraldehyde, 4% paraformaldehyde and 0.1 M sodium cacodylate buffer) and analyzed in transmission and scanning electron microscopes. The different photoperiods had no effect on the ovarioles' ultrastructure. Each ovariole is covered by a thick sheath constituted by a homogeneous and filamentous material. In the terminal filament, there are cells with large nuclei, some with scarce cytoplasm and projections cytoplasmatic, besides filamentous structures assuming characteristic of conjunctive tissue. In the germarium, the germ cells are big with large nuclei, scarce cytoplasm and plasma membrane containing interdigitations. The follicular cells are small with a small nucleus, yet presenting cytoplasmatic projections. In the vitellarium the follicular cells suffer modifications in their morphology varying from cubic to flat.KEY WORDS: Grasshopper, female reproductive system, ovary, morphology RESUMO -A pesquisa teve o objetivo de avaliar a ultra-estrutura dos ovaríolos de Tropidacris collaris (Stoll), submetido aos fotoperíodos de 10L:14E, 12L:12E e 14L:10E. Foram utilizadas 60 ninfas (30 machos e 30 fêmeas) no último estágio de desenvolvimento, sendo colocados 10 casais em cada tratamento. Trinta dias após atingirem o estágio adulto, as fêmeas foram sedadas com éter etílico e dissecadas sob estereomicroscópio. Os ovaríolos foram fixados em Karnovsky (glutaraldeido 2,5%, paraformaldeído 4% e tampão cacodilato de sódio 0,1 M) e analisados em microscopia eletrônica de transmissão e varredura. Os resultados mostraram não haver influência dos fotoperíodos sobre a ultraestrutura dos ovaríolos, onde estes apresentaram-se revestidos por uma bainha espessa constituída por um material homogêneo e filamentoso. Na região do filamento terminal observaram-se células com núcleos volumosos, algumas com citoplasma escasso, além de estruturas filamentosas assumindo característica de tecido conjuntivo. No germário, as células germinativas são maiores, com núcleos volumosos, escassos citoplasma e membrana celular com interdigitações. As células foliculares são menores com núcleo pequeno, apresentando ainda projeções citoplasmáticas. No vitelário as células foliculares sofrem modificações na sua morfologia, variando de cúbica a achatada. PALAVRAS-CHAVE: Gafanhoto, aparelho reprodutor feminino, ovário, morfologiaNo Brasil, a presença e o aumento da população dos gafanhotos estão ligadas certamente ao desmatamento e aos novos tipos de manejos de culturas agroflorestais...

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“…Most common is the integration of multiple signals to govern complex life cycles that include diapause and adjustments of growth (see above). It is significant that even when the reliable, frequent, and recognizable signals from photoperiod are available, most species integrate information from temperature or food to modify this photoperiodic control (e.g., Goehring and Oberhauser 2002;Luker et al 2002). Evidently, even a small contribution of additional evidence from other cues about likely future environmental changes has adaptive value (Danks 2002a).…”

Section: Responsiveness To Environmental Signalsmentioning

confidence: 99%

Insect adaptations to cold and changing environments

Danks¹

2006

Can Entomol

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Abstract-A review of insect adaptations for resistance to cold and for life-cycle timing reveals the complexity of the adaptations and their relationships to features of the environment. Cold hardiness is a complex and dynamic state that differs widely among species. Surviving cold depends on habitat choice, relationships with ice and water, and synthesis of a variety of cryoprotectant molecules. Many aspects are time-dependent and are integrated with other factors such as taxonomic affinity, resource availability, natural enemies, and diapause. Timing adaptations reflect the fact that all environments change over many different time frames, from days to thousands of years. Environments differ in severity and in the extent, nature, variability, and predictability of change, as well as in how reliably cues indicate probable conditions in the future. These differences are reflected by a wide range of insect life-cycle systems, life-cycle delays, levels of responsiveness to various environmental signals, genetic systems, and circadian responses. In particular, the degree of environmental change, its predictability on different time frames, and whether it can be monitored effectively dictate the balance between fixed and flexible timing responses. These same environmental features have to be characterized to understand cold hardiness, but this has not yet been done. Therefore, the following key questions must be answered in order to put cold hardiness into the necessary ecological context: How much do conditions change? How consistent is the change? How reliable are environmental signals?Résumé-La présente rétrospective des adaptations pour la résistance au froid et l'ajustement temporel des cycles biologiques illustre la complexité des adaptations et leurs relations aux caractéristiques du milieu. La résistance au froid est un état dynamique et complexe qui varie considérablement d'une espèce à l'autre. La survie au froid dépend du choix de l'habitat, des relations avec la glace et l'eau et de la synthèse d'une gamme de molécules cryoprotectrices. Plusieurs des aspects sont reliés au temps et sont aussi intégrés à d'autres facteurs, tels que l'affinité taxonomique, la disponibilité des ressources, les ennemis naturels et la diapause. Les adaptations d'ajustement temporel sont reliées au fait que tous les milieux changent à des échelles temporelles multiples, allant de jours à plusieurs millénaires. Les milieux différent entre eux quant à la rigueur et à l'étendue, la nature, la variabilité et la prévisibilité du changement; de plus, les indices des conditions futures probables y sont plus ou moins fiables. Ces différences se reflètent dans les systèmes de cycles biologiques des insectes, les délais dans les cycles biologiques, les degrés de réaction aux divers signaux environnementaux, les systèmes génétiques et les réponses circadiennes. En particulier, le degré de changement environnemental, sa prévisibilité aux différentes échelles temporelles et la possibilité d'en faire un suivi efficace déterminent l'équilibr...

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Reproductive Responses to Photoperiod by a South Florida Population of the GrasshopperRomalea microptera(Orthoptera: Romaleidae)

Cited by 20 publications

References 25 publications

Effect of photoperiod on parasitization by Trichogramma principium (Hymenoptera: Trichogrammatidae)

Effect of photoperiod on parasitization by Trichogramma principium (Hymenoptera: Trichogrammatidae)

Ultra-estrutura dos ovaríolos de Tropidacris collaris (Stoll) (Orthoptera: Romaleidae) submetido a três fotoperíodos

Insect adaptations to cold and changing environments

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