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ABSTRACT: We studied the ability of Tenebrio molitor L. (Coleoptera: Tenebrionidae) to self-select optimal ratios of two dietary components to approach nutritional balance and maximum fitness. Relative consumption of wheat bran and dry potato flakes was determined among larvae feeding on four different ratios of these components (10, 20, 30, and 40% potato). Groups of early instars were provided with a measured amount of food and the consumption of each diet component was measured at the end of 4 wk and again 3 wk later. Consumption of diet components by T. molitor larvae deviated significantly from expected ratios indicating nonrandom self-selection. Mean percentages of dry potato consumed were 11.98, 19.16, 19.02, and 19.27% and 11.89, 20.48, 24.67, and 25.97% during the first and second experimental periods for diets with 10, 20, 30, and 40% potato, respectively. Life table analysis was used to determine the fitness of T. molitor developing in the four diet mixtures in a no-choice experiment. The diets were compared among each other and a control diet of wheat bran only. Doubling time was significantly shorter in groups consuming 10 and 20% potato than the control and longer in groups feeding on 30 and 40% potato. The self-selected ratios of the two diet components approached 20% potato, which was the best ratio for development and second best for population growth. Our findings show dietary self-selection behavior in T. molitor larvae, and these findings may lead to new methods for optimizing dietary supplements for T. molitor.
Environmental Entomology 10/2011; 40(5):1285-94. · 1.56 Impact Factor
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Florida Entomologist 09/2009; · 1.36 Impact Factor
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ABSTRACT: The efficacy of three chitin synthesis inhibitors, diflubenzuron, hexaflumuron, and chlorfluazuron, incorporated into a novel bait matrix to kill the Formosan subterranean termite, Coptotermes formosanus Shiraki, was evaluated in the laboratory. The bait matrix was significantly preferred by C. formosanus over southern yellow pine wood in a two-choice feeding test. Bait formulations containing 250 ppm of the three chitin synthesis inhibitors were presented to termite nests with 2,500 individuals (80% workers and 20% soldiers) in the presence of alternative food sources consisting of cardboard and southern yellow pine, Pinus taeda L., wood. None of the bait formulations were significantly repellent or feeding deterrent to the termite workers evidenced by the lack of full consumption of alternative food sources. All nests presented with the bait formulations died within 9 wk, whereas the control nests (bait with no chitin synthesis inhibitors) remained alive 6 mo after the end of the study. No significant differences in consumption were observed among the chitin synthesis inhibitor treatments. Importance of this study for the improvement of current bait technology is discussed.
Journal of Economic Entomology 05/2001; 94(2):506-10. · 1.70 Impact Factor
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ABSTRACT: The feeding preferences of the Formosan subterranean termite, Coptotermes formosanus Shiraki, were tested in three separate experiments on 28 different wood species. Experiment 1 was a multiple-choice test designed to test relative preferences among 24 wood species commercially available in New Orleans, LA. Experiment 2 was a similar study designed to test relative preferences among 21 wood species shown or reported to be unpalatable to the Formosan subterranean termite. Experiment 3 was a no-choice test to examine the feeding deterrence of the 10 least preferred wood species. Preference was determined by consumption rates. Birch (Betula alleghaniensis Britton), red gum (Liquidambar styraciflua L.), Parana pine [Araucaria angustifolia (Bert.) 1, sugar maple (Acer saccharum Marsh.), pecan (Carya illinoensis Wangenh.), and northern red oak (Quercus rubra L.) were the most preferred species by C. formosanus in order of consumption rate. All of these species were significantly more preferred than southern yellow pine (Pinus taeda L.), widely used for monitoring. Sinker cypress [ = old growth bald cypress, Taxodium distichum (L.)], western red cedar (Thuja plicata Donn), Alaskan yellow cedar (Chamaecyparis nootkatensis D. Don), eastern red cedar (Juniperus virginiana L.), sassafras [Sassafras albidum (Nutt.)], Spanish cedar (Cedrella odorata L.), Honduras mahogany (Swietenia macrophyla King), Indian rosewood (Dalbergia latifolia Roxb.), Honduras rosewood (D. stevensonii Standl.), and morado (Machaerium sp.) induced significant feeding deterrence and mortality to C. formosanus. The last eight species produced 100% mortality after 3 mo.
Journal of Economic Entomology 05/2001; 94(2):516-23. · 1.70 Impact Factor
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ABSTRACT: A laboratory culture of Catolaccus grandis (Burks), an ectoparasitoid of the boll weevil, Anthonomus grandis grandis Boheman, was exposed to lethal and sublethal doses of insecticides and an insect growth regulator using a spray chamber bioassay. Materials tested were azinphos-methyl, endosulfan, fipronil, malathion, cyfluthrin, dimethoate, spinosad, methyl parathion, acephate, oxamyl, and tebufenozide. At full rates, spinosad was significantly less toxic to female C. grandis than other treatments except endosulfan. Fipronil and malathion were significantly more toxic to females than other treatments. Most of the chemicals tested were highly toxic to male C. grandis; spinosad was least toxic. At reduced rates, most of 4 selected chemicals tested were low in toxicity to C. grandis; however, a reduced rate of malathion was significantly more toxic to females than other treatments. No C. grandis pupae developed from parasitism during a 24-h treatment period with malathion or spinosad. The sex ratio of progeny from sprayed adults appeared to be unaffected by the treatments.
Journal of Economic Entomology 05/2000; 93(2):300-3. · 1.70 Impact Factor
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ABSTRACT: A glass vial bioassay was used to determine the toxicity of 10 insecticides to 3 strains of the boll weevil, Anthonomus grandis grandis Boheman, ectoparasitoid Catolaccus grandis (Burks). Technical-grade samples of dimethoate, endosulfan, oxamyl, acephate, malathion, azinphos-methyl, cyfluthrin, methyl parathion, spinosad, and fipronil were used in bioassays. Three strains of C. grandis were tested: 2 in vivo-reared strains, (i.e., the In Vivo strain and the Sinaloa strain), and 1 in vitro-reared strain reared on an artificial diet completely devoid of insect components (i.e., the In Vitro strain). Endosulfan, spinosad, and azinphos-methyl were significantly less toxic to the In Vivo strain than other treatments. Endosulfan was also significantly less toxic to the Sinaloa strain than other treatments. Azinphos-methyl was significantly less toxic to the In Vitro strain than other treatments. In addition, malathion, the insecticide most widely used in boll weevil eradication, was significantly more toxic to the In Vitro strain than other treatments. However, it cannot be determined directly from the data which insecticides may be more toxic to C. grandis in the field. Bioassays must be refined so that risks to natural enemies can be predicted reliably. In so doing, chemical insecticides may be developed and used that may be selective (i.e., more toxic to a pest than to a beneficial species). The data reported herein, however, is likely to be useful to many ecotoxicologists.
Journal of Economic Entomology 03/1999; 92(2):309-313. · 1.70 Impact Factor
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ABSTRACT: Catolaccus grandis (Burks), an ectoparasitoid of the boll weevil, Anthonomus grandis, grandis (Boheman) (Coleoptera: Curculionidae), was reared in laboratory conditions on the cowpea weevil, Callosobruchus maculatus (F.), as a factitious host to reduce costs on a mass propagation system. Total fecundity, daily oviposition, net reproductive rate, and sex ratio were evaluated and compared among females reared on A. grandis and C. maculatus. The larval data showed that C. maculatus is a viable alternative host for the rearing of C. grandis. After 10 generations of continuous rearing on C. maculatus, C. grandis females showed a significant switch in host acceptance as an oviposition site and remained even after rearing on A. grandis for 1 generation. For this reason, we do not recommend rearing C. grandis on C. maculatus for >1 generation. However, the use of A. grandis and C. maculatus as hosts may be an acceptable practice, given that host preference was not significantly affected on 1st-generation C. grandis females reared on C. maculatus.
Environmental Entomology 01/1999; 28(1):137-141. · 1.56 Impact Factor
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ABSTRACT: Augmentation and release of the ectoparasitoid Catolaccus grandis (Burks) against the boll weevil, Anthonomus grandis grandis Boheman, has relied on the production of boll weevils for the past 15 yr. Eliminating this dependence on a host that is expensive to rear could make this technology commercially viable. Seven species of insects that are more easily reared than the boll weevil were tested as factitious hosts of C. grandis. Four species were lepidopterans—Galleria mellonella (L.), Helicoverpa zea (Boddie), Heliothis virescens (F.), and Chilo plejadellus Zincken. Only H. zea and H. virescens stimulated oviposition by C. grandis; nevertheless this parasitoid did not complete development in any of these lepidopterans. The other 3 species were coleopterans—Chalcodermus aeneus Boheman, Anthonomus eugenii Cano, and Callosobruchus maculatus (F.). Females of C. grandis oviposited and parasitoids completed development in all coleopteran species. C. grandis females reared on C. maculatus oviposited significantly more eggs per day than those reared on A. eugenii or C. aeneus. Chemical analyses showed that the concentrations of proline, histidine, glutamine, and tyrosine in C. maculatus and A. eugenii hemolymph most closely resembled those of A. g. grandis hemolymph. The effectiveness of the factitious hosts to stimulate oogenesis was indirectly tested by comparing oviposition rates of females exposed to the factitious hosts to those of naive females. Even though A. eugenii and C. maculatus stimulated oogenesis (conditioning) in C. grandis females after 3 d of exposure, the degree of stimulation was significantly lower than that induced by exposure to A. g. grandis prepupae. The results indicate that C. maculatus is a promising factitious host to rear and condition C. grandis females.
Environmental Entomology 03/1998; 27(2):499-507. · 1.56 Impact Factor
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ABSTRACT: The biological characteristics of the ectoparasitoid Catolaccus grandis (Burks) were evaluated after 1, 2, 5, and 10 generations of in vitro-rearing and compared with parasitoids reared on boll weevil, Anthonoms grandis grandis Boheman, larvae. Pupal weight of females was not significantly affected after 10 generations of in vitro-reared wasps. Fecundity of C. grandis was not significantly reduced after 5 generations of in vitro-rearing. However, the in vitro F10 showed a significant reduction in fecundity. Females reared on boll weevils had a higher pupal weight and fecundity than females reared in vitro, but in vitro-reared females exhibited significantly higher survival during the period of most intensive reproductive activity. The movement, searching capacity, and survival under field conditions of in vitro and in vivo-reared C. grandis were compared in Ricardo and Lyford, TX. Dispersal ability and searching capacity was not significantly different within a 30-m radius for parasitoid females reared by either method. However, a significantly higher proportion of stations with parasitism was recorded from in vivo-reared C. grandis. at a 60-m radius from the release point. Nevertheless, no significant difference in boll weevil mortality induced by parasitism was recorded between the 2 methods. This shows that the use of artificial diets is a promising method for mass propagating C. grandis.
Journal of Economic Entomology 01/1998; 91(1):101-109. · 1.70 Impact Factor
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ABSTRACT: The effect of different concentrations of fructose and glucose on the longevity of the boll weevil, Anthonomus grandis grandis Boheman, ectoparasitoid Catolaccus grandis (Burks) was tested. Parasitoid females feeding sugar concentrations of 30% had a significantly increased longevity compared with females feeding 50 and 70% sugar solutions. Host-feeding on boll weevil larvae did not significantly increase longevity. In the absence of a carbohydrate source, host-feeding was ineffective maintaining C. grandis alive for >2.5 d. Dissections showed that C. grandis is a synovigenic and autogenous parasitoid, but providing C. grandis females with diets supplemented with amino acids and boll weevil haemolymph did not increase oögenesis. Females with oviposition experience, on the other hand, produced 4 times as many eggs as did inexperienced females regardless of the quality of the adult diet provided. However, adult nutrition was important for egg production after host contact. Catolaccus grandis females experienced in oviposition produced significantly more eggs when a supplemental diet was provided in the absence of host-feeding opportunities. Exposure of the parasitoids to encapsulated weevil larvae for at least 2 d before the field release is recommended.
Annals of the Entomological Society of America 06/1996; 89(4):555-563. · 1.32 Impact Factor
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ABSTRACT: The effect of the venom of the ectoparasitoid Catolaccus grandis (Burks) on boll weevil, Anthonomus grandis grandis Boheman growth, development, and survival, and parasitoid development were investigated. Microscopic observations showed that 81.4% of parasitized weevils were not paralyzed. The percentage of unparalyzed hosts correlated positively with the age of the parasitoid females and negatively with the degree of superparasitism. The growth of envenomed hosts was reduced and envenomed hosts did not complete development. However, parasitoid development was not affected in the absence of venom. The concentration and ratios of free amino acids in the boll weevil haemolymph were significandy affected by C. grandis venom. Similar changes in free amino acids in boll weevil haemolymph were observed in prepupae not exposed to parasitism, but artificially parasitized by 1st instar C. grandis. The presence of a similar envenomizing agent in the 1st instar parasitoids is discussed.
Annals of the Entomological Society of America 10/1995; 88(6):800-808. · 1.32 Impact Factor
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ABSTRACT: We studied the effects of densities of ectoparasitoids (per liter of cage volume) and host-parasitoid ratios on the reproductive potential of parasitoid females. Ectoparasitoid, Gatolaccus grandis (Burks), densities were varied from 3.8 to 37.7 females per liter volume of oviposition cages (petri dishes). Host-parasitoid ratios ranged from 0.2 to 20 3rd instars of the boll weevil. Authonomus grandis grandis (Boheman), per parasitoid fenmle per day. Fecundity of C. grandis females was not affected by changes in the density of female adults in oviposition cages. However, adult mortality increased when female parasitoid density exceeded 15 females per liter of cage volume. Mean percentage of parasitism of the boll weevil hosts decreased from 100 to 33% when the host-parasitoid ratio increased from 0.2 to 20.0 weevil larvae per C. grandis female per day. Parasitoid fecundity was inversely proportional to the percentage of parasitized host larvae. A higher proportion (69-75%) of fertilized eggs were oviposited when host-parasitoid ratios were between 1 and 20 host larvae per C. grandis female than when ratios were <1 host per female (40-41%). Low host-parasitoid ratios reduced the rate of reproduction in C. grandis, whereas high parasitoid densities increased intraspecific competition and parasitoid mortality. Under laboratory conditions, the most efficient host-parasitoid ratio was 5-15 host larvae per female parasitoid per day.
Environmental Entomology 09/1995; 24(5):1333-1337. · 1.56 Impact Factor
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ABSTRACT: Termite foods mixed together in a matrix suitable to be used as baits and attractants for termites are provided. They comprise cellulose, naphthalenic compounds, water and potentially other termite-preferred nutrients. Methods of monitoring the presence of termites using such matrices and methods of controlling termites using such matrices to deliver termite toxins are also provided.
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ABSTRACT: Effects of the chitin synthesis inhibitors (CSIs) diflubenzuron; hexaflumuron, and lufenuron on the Formosan subterranean termite, Coptotermes formosanus Shiraki, primary reproductives were studied in the laboratory. Incipient colonies were established by collecting and pairing C. formosanus alates and placing them in dishes containing an artificial diet. Three groups of 56 colonies each were fed with a diet containing 10 ppm of one of each of the CSIs and were compared with a control group fed with an untreated diet. All eggs oviposited by treated young queens failed to hatch at the end of 6 mo. Estimated queen fecundity was significantly lower in the lufenuron treatment compared with the control group. Fecundity of hexaflumuron-treated queens did not differ significantly from that of queens from the control group and the other treatments. Adult mortality was significantly higher in the diflubenzuron and lufenuron treatments than in the control group at the end of 6 mo., but not in the hexaflumuron treatment. All the pairs died within 8 mo. in the diflubenzuron and lufenuron treatments, even after treatment was suspended at the end of 6 mo. Mortality in the hexaflumuron treatment was significantly higher than in the control group by the end of 9 mo. The three CSIs tested eliminated reproduction in C. formosanus by preventing egg hatching and induced adult mortality. Possible mechanisms by which CSIs induce termite adult death are discussed.
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ABSTRACT: The wood of 11 plant species was evaluated as a food source significantly impacting the growth and survival of incipient colonies of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Colonies of C. formosanus feeding on pecan, Carya illinoensis (Wangenh.), and red gum, Liquidambar styraciflua L., produced significantly more progeny than colonies feeding on other wood species tested. Progeny of colonies feeding on pecan and American ash, Fraxinus americana L., had significantly greater survival than progeny of colonies feeding on other wood species. Colonies feeding on a nutritionally supplemented cellulose based matrix showed similar fitness characteristics as colonies feeding on the best wood treatments. These results indicate that differences observed in colony fitness can be partially explained by nutritional value of the food treatment, raising the possibility that wood from different tree species have different nutritional values to the Formosan subterranean termites. Colonies feeding on loblolly pine, Pinus taeda L., and ponderosa pine, Pinus ponderosa Laws., had significantly lower survival and produced significantly fewer workers and soldiers than colonies feeding on other wood species. Colony survival from 90 to 180 d of age and from 90 to 360 d of age was significantly correlated with the number of workers present at 90 d of colony age, indicating that colony survival depends on the presence of workers. Wood consumption in a multiple-choice study was significantly correlated with colony fitness value. This suggests that feeding preference of C. formosanus is at least partially influenced by the nutritional value of the food source.
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ABSTRACT: The importance of lipids for queen fecundity and colony growth of Coptotermes formosanus Shiraki was studied. Groups of 100 incipient colonies of C. formosanus were reared on artificial diet containing nine different soy lecithin concentrations. Eggs were counted every 15 d for a 5-mo period at 27 ± 1°C, 93 ± 5% RH, and 0:24 h (L:D) photoperiod. Fecundity per queen was estimated using a developmental rate-based graphic integration technique. At the end of a 1-yr period, the progeny of each colony was counted and recorded. Analysis of variance showed significant differences in queen fecundity and hatched progeny in colonies raised on various diets. Single linear regression analysis showed a small but significant linear increase in queen fecundity and hatched progeny per colony with increasing lecithin concentration. Increase in lecithin concentration explained 2, 4, and 8% of the increase in queen fecundity of colonies surviving 6 mo and 1 yr and number of workers and soldiers in 1 yr-old colonies, respectively. This indicates that, although intake of lipids increases queen fecundity and colony growth of C. formosanus, other factors not measured in this study alone or in combination with lecithin play major roles.
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ABSTRACT: The variation in instar number and the pattern of sequential instar development time of Tenebrio molitor L. (Coleoptera: Tenebrionidae) was studied under 4 different diet regimes. Addition of dietary supplements consisting of dry potato or a mix of dry potato and dry egg whites significantly reduced the number of larval instars and total development time. The pattern of sequential stadia length showed regularity and low variability in instars 5 to 9. Stadia length continuously increased between instar 10 and the last instar before pupation (P-1). Instar number significantly impacted total development time and was also significantly correlated with stadia length. The length of each stadium was significantly reduced as the protein content in diets was increased. The length of the last stadium (P-1) was regular within food treatments regardless of sequential instar number, but P-1 was also significantly affected by nutrition in a similar way as all the sequential stadia. The pattern of instar variation is discussed in regard to the insertion of new instars based on variation of stadia length.
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ABSTRACT: An improved artificial diet or growth medium for rearing the insect parasitoid Catolaccus grandis is disclosed. The growth medium is composed of amino acid, mineral, vitamin, lipid, and carbohydrate fractions which are present in amounts and proportions effective to support growth of Catolaccus grandis, and the amino acid fraction includes alanine, glutamic acid, histidine and proline at concentrations of about 3.0-5.0%, 8.4-9.4%, 10.0-15.1% and 11.7-12.8%, by weight, respectively. The growth medium is suitable for mass propagation of C. grandis from egg to adult for their subsequent release as biocontrol agents. Alternatively, the growth medium may be used to support growth of adult female wasps of C. grandis for use as breeding stock for continued mass propagation.
