Habitats and foraging movements of larvae of Molanna uniophila Vorhies (Trichoptera: Molannidae) were studied during four summers in Pratt Lake, Michigan. Larvae lived and fed in shallow (&#x3c;10&#x2009;cm), sand-bottomed lake margins, where macrophyte densities ranged from 86 to 452 stems/m2. Average densities of larvae varied fivefold between years (2.7 versus 13.6 individuals/m2), but larval densities did not vary significantly between habitat patches with low (120 stems/m2) and high (360 stems/m2) macrophyte densities. Larvae and their cases exhibited strong patterns of simple, linear growth. Diets of larvae were dominated by amorphous detritus, plant debris, diatoms, and filamentous algae, but midges, cladocerans, and other microscopic aquatic animals also were consumed. Larvae shifted their bodies and cases forward across the surface sediments up to 4 times/minute while foraging, moving as much as 2.5&#x2009;m/hour. Movements and distances traveled while feeding increased significantly with increased water temperatures, peaking during midafternoon hours. Distances moved by feeding larvae did not differ between habitats with low versus high macrophyte densities. Larvae foraged most actively during daylight hours and did not selectively utilize macrophyte beds as partial refugia from potential predators while feeding.

Neal D. Mundahl

Erik D. Mundahl

Habitats and Foraging Movements of Larvae of Molanna uniophila Vorhies (Trichoptera: Molannidae) in Pratt Lake, Michigan, USA

Although tropical insect populations are generally regarded as constant and stable over time, some of these tropical populations, including butterflies, may fluctuate according to precipitation and temperature variation, specialized feeding patterns, and density-dependent factors. Heliconiini butterfly populations are generally regarded as stable over time because of the presence of host-plants and absence of diapause. However, peaks of abundance occur in subtropical Heliconius populations, and opposite trends concerning stability are found in the literature. Here we further investigate the dynamics of subtropical Heliconius butterflies by assessing a population of the species Heliconius sara apseudes from southeastern Brazil. We estimated individual apparent survival probability and population growth rate while accounting for the imperfect detectability of individuals using mark-recapture models to evaluate the population dynamics. Adult males presented slightly higher weekly survival estimates than females. Contrary to the common pattern described in the literature for Heliconius populations we observed a rapid decline on the adult population by the end of the mating season, possibly leading to local extinction. We discuss the potential drivers for such dynamics.

Thadeu Sobral-Souza

Ronaldo Bastos Francini

Murilo Guimar&#xe3;es

Woodruff Withman Benson

Short-Term Dynamics Reveals Seasonality in a Subtropical Heliconius Butterfly

Optimal flight in butterflies depends on structural features of the wings and body, including wing size, flight muscle size, and wing loading. Arguably, there is no butterfly for which flight is more important than the monarch (Danaus plexippus), which undergoes long-distance migrations in North America. We examined morphological features of monarchs that would explain the apparent higher migratory success and flight ability of females over males. We examined 47 male and 45 female monarch specimens from a project where monarchs were reared under uniform conditions. We weighed individual body parts, including the thorax (flight muscle) and wings, and computed wing loading and wing thickness for all specimens. When we compared each morphological trait between sexes, we found that females did not differ from males in terms of relative thorax (wing muscle) size. Females were generally smaller than males, but females had relatively thicker wings than males for their size, which suggests greater mechanical strength. Importantly, females had significantly lower wing loading than males (7&#x25; lower). This would translate to more efficient flight, which may explain their higher migratory success. Results of this work should be useful for interpreting flight behavior and/or migration success in this and other Lepidopteran species.

Andrew K. Davis

Michael T. Holden

Measuring Intraspecific Variation in Flight-Related Morphology of Monarch Butterflies (Danaus plexippus): Which Sex Has the Best Flying Gear?

The tamarind weevil, Sitophilus linearis Herbst (Coleoptera: Curculionidae), is an important pest of tamarind and other Caesalpinioideae. Investigating its life history is important in the implementation of management strategy. Its life history was monitored daily to understand its developmental biology on tamarind seed following standard procedures under laboratory conditions of 24&#x2013;30&#xb0;C temperature, 60&#x2013;70&#x25; relative humidity, and 12L&#x2009;:&#x2009;12D photoperiod. The egg incubation period lasted 3.17 &#xb1; 0.07 days. A mated female of S. linearis laid an average of 165 &#xb1; 5.78 eggs during an oviposition period of 86.8 &#xb1; 2.47 days. There were four larval instars, with a total larval developmental period of 16 days. The pupal period lasted 8 days, and adult lived 108.5 &#xb1; 3.61 days. The overall growth ratio for the four instars was 1.33. There was a regular relationship and significant correlation (<svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2063904pt" id="M1" height="8.55521pt" version="1.1" viewBox="-0.0498162 -8.34882 42.2948 8.55521" width="42.2948pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-115" d="M393 379C402 394 400 411 393 422C384 437 365 448 348 448C301 448 237 372 186 285H182L193 335C210 408 205 448 178 448C150 448 80 402 29 344L45 321C80 355 114 373 122 373C128 373 130 365 124 330C106 228 76 98 50 -5L57 -12C82 -5 112 3 132 6L172 203C196 256 234 304 254 329C275 355 293 367 306 367C318 367 330 360 342 348C347 343 355 343 365 350S386 367 393 379Z" /><glyph.data ascent="3473" descent="-2876" horiz-adv-x="422" vert-adv-y="422" /></g><g transform="matrix(.013,0,0,-0.013,9.12,0)"><path id="g117-34" d="M535 323V373H52V323H535ZM535 138V188H52V138H535Z" /><glyph.data ascent="3473" descent="-2876" horiz-adv-x="587" vert-adv-y="587" /></g><g transform="matrix(.013,0,0,-0.013,20.383,0)"><path id="g113-49" d="M241 635C89 635 35 457 35 312C35 153 89 -12 240 -12C390 -12 443 166 443 312C443 466 390 635 241 635ZM238 602C329 602 354 454 354 312C354 172 330 22 240 22C152 22 124 173 124 313S148 602 238 602Z" /><glyph.data ascent="3473" descent="-2876" horiz-adv-x="480" vert-adv-y="480" /></g><g transform="matrix(.013,0,0,-0.013,26.623,0)"><path id="g113-47" d="M113 -12C146 -12 170 11 170 46C170 78 146 103 114 103S58 78 58 46C58 11 82 -12 113 -12Z" /><glyph.data ascent="3473" descent="-2876" horiz-adv-x="228" vert-adv-y="228" /></g><g transform="matrix(.013,0,0,-0.013,29.587,0)"><path id="g113-58" d="M244 635C114 635 38 519 38 422C38 317 111 240 217 240C236 240 255 244 277 256L345 292C311 140 203 39 59 15L64 -15C89 -15 150 -5 204 17C339 72 440 202 440 386C440 521 368 635 244 635ZM228 602C326 602 352 479 352 390C352 370 351 347 348 324C327 308 293 296 258 296C174 296 124 369 124 458C124 517 152 602 228 602Z" /><glyph.data ascent="3473" descent="-2876" horiz-adv-x="480" vert-adv-y="480" /></g><g transform="matrix(.013,0,0,-0.013,35.828,0)"><path id="g113-53" d="M456 178V225H360V632H320C217 496 115 347 20 206V178H280V106C280 40 276 34 189 27V0H445V27C364 34 360 39 360 106V178H456ZM280 225H82C149 335 214 431 278 520H280V225Z" /><glyph.data ascent="3473" descent="-2876" horiz-adv-x="480" vert-adv-y="480" /></g></svg>) between the stages of larval development and head capsule width.

James Adebayo Ojo

Adebayo Amos Omoloye

Life History of the Tamarind Weevil, Sitophilus linearis (Herbst) (Coleoptera: Curculionidae), on Tamarind Seed

This work aims to study for the first time the chemical composition and evaluate insecticidal and repellent effects of essential oils of Premna angolensis and Premna quadrifolia leaves, against Sitotroga cerealella, an insect pest of rice stocks as alternatives to synthetic pesticides. The GC-MS analysis showed that essential oil of P. angolensis contains 29 compounds representing 96.1&#x25; of the oil and 42 compounds corresponding to 91&#x25; for the essential oil of P. quadrifolia. The main constituents regardless of the species were &#x3b2;-caryophyllene (13.1&#x25;), (E)-&#x3b2;-caryophyllene (13.5&#x25;), octen-3-ol (3.2&#x25;&#x2013;28&#x25;), phytol (3.7&#x25;&#x2013;4.9&#x25;), &#x3b2;-elemene (1.4&#x25;&#x2013;21&#x25;), globulol (11.2&#x25;), germacrene-D (8.9&#x25;), &#x3b1;-humulene (2.9&#x25;&#x2013;6.4&#x25;), &#x3b1;-pinene (5&#x25;), sabinene (3.7&#x25;), &#x3b4;-cadinene (0.4&#x25;&#x2013;3.3&#x25;), and linalool (3.3&#x25;). The results of laboratory tests showed that both essential oils have insecticidal and repellent effects on S. cerealella. Presenting the results, the damage caused by the adults and larvae of S. cerealella was evaluated by calculating the percentage of grains attacked and weight loss thereof. The results suggest that volatile extracts of P. angolensis and P. quadrifolia can be used as alternatives to synthetic chemicals in paddy protection against S. cerealella.

Elvis Adjalian

Philippe Sessou

Th&#xe9;ophile Odjo

Gilles Figueredo

Dansou Kossou

F&#xe9;licien Avlessi

Chantal Menut

Dominique Sohounhlou&#xe9;

Chemical Composition and Insecticidal and Repellent Effect of Essential Oils of Two Premna Species against Sitotroga cerealella

Rice yellow mottle virus (RYMV) is the major viral constraint to rice production in Africa. RYMV was first identified in 1966 in Kenya and then later in most African countries where rice is grown. Several studies have been conducted so far on its evolution, pathogenicity, resistance genes, and especially its dissemination by insects. Many of these studies showed that, among RYMV vectors, insects especially leaf-feeders found in rice fields are the major source of virus transmission. Many studies have shown that the virus is vectored by several insect species in a process of a first ingestion of leaf material and subsequent transmission in following feedings. About forty insect species were identified as vectors of RYMV since 1970 up to now. They were essentially the beetles, grasshoppers, and the leafhoppers. For this review, we presented the chronology of their identification. Also, the biology, ecology, host range, distribution, and caused damage of these insects were briefly summarized.

Augustin Koudamiloro

Francis Eegbara Nwilene

Abou Togola

Martin Akogbeto

Insect Vectors of Rice Yellow Mottle Virus

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Journal of Insects