The Life History and Host Range of Charidotis pygmaea (Col.: Chrysomelidae), a Biological Control Agent for Lantana montevidensis (Verbenaceae)

The life cycle and host range of Charidotis pygmaea Klug were investigated to assess its suitability for release as a biological control agent for Lantana camara L. and L. montevidensis (Sprengel) Briquet. Adults fed and deposited eggs on the underside of leaves of both species. They generally laid fewer eggs in the dry winter months when lantana yellows or drops its leaves. Larvae fed on the upper leaf surface and pupation occurred on the leaves or stems. Development from egg to adult took approximately 50 days. Survival to the adult stage was greater, and the development time was shorter on L. montevidensis than on all varieties of L. camara tested, suggesting that the agent would be ineffective against L. camara. Forty-two plant species were tested to determine host specificity in choice oviposition and larval feeding trials. These demonstrated that C. pygmaea did not pose a threat to non-target species. Consequently, C. pygmaea was approved for release in Australia and through its ability to survive the dry season, should assist in the control of L. montevidensis.     

Interspecific differences among swallowtail larvae (Lepidoptera: Papilionidae) in susceptibility to aristolochic acids and berberine

Abstract. 1. The larvae of four swallowtail butterfly species, Papilio polyxenes Fabr. in the Papilionini, Parides bunichus (Hübner) and Battus polydamas (L.) in the Troidini, and Eurytides marcellus (Cramer) in the Graphiini, were grown on host leaves to which test compounds had been added.
2. The test chemicals are biosynthetically related. Berberine, a 1-benzyl-tetrahydroisoquinoline-related (1-BTIQ) alkaloid, is found in many rutaceous hosts of the Papilionini; laudanosine, a simpler 1-BTIQ alkaloid, is found in the Papaveraceae, plants on which no papilionids feed; aristolochic acids are found only in the Aristolochiaceae, hosts of the Troidini.
3. Swallowtail larvae can tolerate the compounds characteristic of their host plants, but not chemicals found in the hosts of other papilionid groups. Diets with laudanosine did not affect the test species.
4. Our results support the contention that plant secondary chemicals, such as berberine and aristolochic acids, are important feeding barriers, and are partially responsible for host specificity in swallowtails.     

Host specificity and host recognition in a chemically-defended herbivore, the tenthredinid sawfly Rhadinoceraea nodicornis

The sawfly Rhadinoceraea nodicornis Konow (Hymenoptera: Tenthredinidae) is a member of a closely related group of species, the tribe Phymatocerini, which feed on the Liliales and Ranunculales. It is known to sequester steroid alkaloids from its host plants, species in the genus Veratrum (Liliales: Melanthiaceae), and to use them as a defence against predators. There are known chemical relationships between the hosts of R. nodicornis and hosts of related sawfly species. We tested whether the R. nodicornis larvae would accept hosts of closely- and more distantly-related sawflies, but found that they accepted only plant species in the genus Veratrum. This specificity was apparently innate, as it was independent of early larval experience. A feeding bioassay showed that the steroid alkaloids from Veratrum nigrum were phagostimulatory for R. nodicornis larvae, suggesting that they may be involved in host recognition. We discuss the possibility that the evolution of recognition of specific compounds may represent the mechanism of host radiation within the Phymatocerini.     

Do Larvae of Bertha armyworm,Mamestra configurata (Walker) (Lepidoptera: Noctuidae), express induced feeding responses?

The Bertha armyworm, Mamestra configurata (Walker) (Lepidoptera: Noctuidae), is a polyphagous Nearctic insect known to feed on over 40 different host plant species, and can be a pest of canola (Brassica napus L. and Brassica rapa L.), flax (Linum usitatissimum L.), and alfalfa (Medicago sativa L.) in the Northern Great Plains. Bertha armyworm is known to sometimes switch hosts through between‐field movements, prompting this study to investigate its adherence to a particular host plant species after completing a period of initial development on it. In a laboratory study, larvae were reared to either their fourth or sixth instars on either intact or excised leaf tissue of one of seven host species, and were then allowed to select feeding hosts from various choices that included canola, B. napus and B. rapa (Brassicaceae), Canada thistle, Cirsium arvense (L.) Scop. (Compositae), flax, L. usitatissimum (Linaceae), field pea and alfalfa, Pisum sativum L. and M. sativa (Leguminosae), and lamb’s quarters, Chenopodium album L. (Chenopodiaceae). In general, Bertha armyworm larvae showed little propensity to feed on the host plant species on which they had been reared in their early life stages. Exceptions occurred for larvae reared on intact tissue of B. rapa and P. sativum, where larvae were subsequently observed feeding on these hosts significantly more frequently than on other host plants. When larvae of Bertha armyworm were reared through early developmental stages on intact plant tissue of a single host, B. rapa was frequently the choice for subsequent feeding. Movements of Bertha armyworm larvae between fields therefore appear to result from larvae that have exploited food resources in one area and are dispersing to regions of improved host plant availability.     

Extreme weather change and the dynamics of oviposition behavior in the pipevine swallowtail, <Emphasis Type="Italic">Battus philenor</Emphasis>

Prospects of global increases in extreme weather change provide incentive to examine how such change influences animal behavior, for example, behavior associated with resource use. In this study, we examined how oviposition behavior in a southern Arizona population of pipevine swallowtails (Battus philenor L.) responded to changes in their Aristolochia host resource and vegetative background caused by the North American monsoon system. Summer monsoon rains resulted in a flush of non-host vegetation and a more than doubling in rate of landings by host-searching females on non-host vegetation. Rates of discovery of the host species A. watsoni Woot. Standl. decreased by 50% after monsoon rains. Rains did not alter host density appreciably, but resulted in significant increases in host plant size and new growth, two indicators of host suitability for B. philenor larvae. After the rains, mean clutch size on individual host plants increased by a factor of 2.5; the mean proportion of host plants encountered on which a female laid eggs also increased significantly. Females were discriminating about the host plants on which they laid eggs after alightment; plants accepted for oviposition were larger, bore more new growth, and bore fewer larvae than rejected plants. Contrary to predictions from foraging theory, degree of discrimination did not change seasonally. Finally, the rate at which eggs were laid increased seasonally, suggesting that oviposition rates were limited more before monsoon rains by the relatively low quality of hosts than they were after the rains by the relatively low rate at which hosts were found. This latter result suggests that, while butterflies possess behavioral flexibility to respond to extreme weather change, such flexibility may have limits. In particular, expected increases in the severity and frequency of droughts may result in reduced oviposition rates, reductions that could have adverse demographic consequences.     

Host specificity of Argopistes tsekooni (Coleoptera: Chrysomelidae), a potential biological control agent of Chinese privet

Chinese privet, Ligustrum sinense Lour., is a perennial semi-evergreen shrub that is a serious invasive weed in the United States. Classical biological control offers the best hope for controlling it in an economic, effective, and persistent way. Host specificity of one of the most promising biological control agents of Chinese privet, a flea beetle, Argopistes tsekooni Chen (Coleoptera: Chrysomelidae), was evaluated in China by using laboratory no-choice and choice tests on 13 species of Oleaceae and eight species in other families that have important economic value. In adult no-choice survival and oviposition tests, the flea beetle fed and survived for 30 d on Syringa oblata Lindl., Jasminum nudiflorum Lindl., and three species in the genus Ligustrum. Females also oviposited on these species, but only larvae from eggs laid on S. oblata and Ligustrum spp. developed successfully. In addition, the beetles did not feed or oviposit on the species of economic importance. In choice tests, adults preferred L. sinense for feeding and oviposition. These results show that A. tsekooni is relatively host specific and warrants further testing as a biocontrol agent of Chinese privet in the United States.     

Attack behavior and host utilization ofAphthona chinchihi (Col.: Chrysomelidae), a potential biological control agent ofEuphorbia esula (Euphorbiaceae, leafy spurge) in North America

Aphthona chinchihi Chen was collected in China feeding on leafy spurge (Euphorbia esula L.). Studies were conducted on its host specificity in the laboratory, using field collected adults and their progeny.Aphthona chinchihi can effectively complement the impact of the other natural enemies of leafy spurge established from Europe in the U.S.A. and Canada. The adults feed on leaves and shoots and the larvae, which cause the main damage to the plant, feed on the hypogeous portion of the plant, seriously stressing the plant and preventing its vegetative spread. The host range ofA. chinchihi was studied with tests on adult feeding and oviposition, larval survival and host suitability, using 40 plant species or varieties distributed in 12 families. The experiments demonstrated that it has a high level of specificity. This flea beetle completed its life cycle only on leafy spurge. Also, because of its ecological valence,A. chinchihi has a very good potential as a biocontrol agent in North America.     

嗅觉和视觉在中华微刺盲蝽对马缨丹定向行为中的作用

对马缨丹(Lantana camara)、黄花马缨丹(Lantana camara cv.‘Flava')和紫花马缨丹(Lantanamontevidensis)花序上中华微刺盲蝽(Campylomma chinensis)的密度调查结果表明,中华微刺盲蝽在3种颜色马缨丹花序上的分布与花序颜色无关(偏相关系数为0.240,P=0.147,n=40),但与花序中的黄胸蓟马数量和花序中小花数的偏相关系数分别为0.512(P＜0.0001,n=0)和0.451(P＜0.0001,n=40),达到极显著水平.中华微刺盲蝽对不同颜色粘卡的试验也表明,该盲蝽寻找植物寄主时,视觉刺激并不起作用.四臂嗅觉仪的试验结果表明,中华微刺盲蝽对马缨丹的气味有强烈的趋向作用.采用固相微萃取和气相-质谱联用技术分析表明,3种马缨丹花序的挥发物有7种相同的化学成分.     

Performance of Lymantria xylina (Lepidoptera: Lymantriidae) on artificial and host plant diets

Lymantria xylina Swinhoe (Lepidoptera: Lymantriidae) is a serious defoliator of hardwood and fruit trees in Taiwan. The larvae of L. xylina feed on >63 species of host plants, belonging to 29 families. Because a large number of larvae are needed for the production of nucleopolyhedrosis virus (NPV) or other related studies, the development of a suitable artificial diet is very important for the mass rearing of this moth in the laboratory. In this study, eight artificial diets, modified from different formulas, and one host plant, Liquidambar formosana Hance, were used to feed L. xylina caterpillars. Through various bioassays (first instar survival trial and long- and short-term feeding trials), the most suitable diet for the L. xylina was selected by performance comparisons with L. formosana. After the first instar survival trial, two of the diets were discarded, because no larva survived on these diets. The results of the long-term feeding trial indicated that the larvae grew successfully on only three kinds of artificial diet. Finally, results of the short-term feeding trial revealed that a diet (diet A), modified from the gypsy moth, Lymantria dispar (L.), formula diet, was the most appropriate for the L. xylina. Larvae fed on diet A had better survival rate, pupal weight, adult size, efficiency of conversion, and relative growth rate than larvae fed on other diets; they did not grow as well as those fed on L. formosana, however, except for pupal and adult weight, and approximate digestibility. In summary, diet A was found to be the best of the artificial diets for the L. xylina and is suitable for mass rearing of this moth in the laboratory.     

Acceptability and suitability of seven plant species for the mealybug Phenacoccus parvus

Survival, development and fecundity of cohorts of the mealybug Phenacoccus parvus Morrison were measured over one generation on seven plant species representing four plant families. Survival, development and fecundity were not significantly higher on the mealybug's principal field host, the weed Lantana camara L. (Verbenaceae), than on other plant species including Lycopersicon esculentum Miller (tomato) and Solanum melongena L. (eggplant). The acceptability of the leaves of the seven plant species to P. parvus first instar crawlers was measured on hatching, after active walking and after food deprivation. Lantana camara was the highest ranked plant species for all treatments. The number of crawlers settling on lower ranked plant species increased with the level of food deprivation.     

双斑长跗跳甲形态特征及行为学观察

双斑长跗跳甲Longitarsus bimaculatus Baly成虫取食美国白蜡(Fraxinus americana L.)叶片,受害叶焦枯脱落;幼虫钻入根内取食,以须根受害最重。描述各虫态的形态特征,并通过室内饲养和野外调查,观察成、幼虫的行为习性,对成虫的活动、取食、交配等行为作了详细报道。     

Why are there feeding and nonfeeding larvae in phytoseiid mites (Acari, Phytoseiidae)?

The larval feeding traits and oviposition behavior of ten phytoseiid mite species were investigated in the presence and absence of prey. Results showed a correlation between prey preferences, the manner of oviposition, and larval feeding behavior. Species with larvae that must feed to develop preferred prey species that were distributed sparsely and laid their eggs in a scattered fashion. Species with larvae that do not need to feed to develop preferred prey species with a high aggregation and laid their eggs in a clumped fashion. The results suggest that nonfeeding larval behavior may be an adaptation to avoid sib-cannibalism, which occurs when eggs are oviposited closer together. Received: October 13, 2000 / Accepted: December 15, 2000     

Experimental studies on parasitization byApanteles Glomeratus V. Relationships between growth rate of parasitoid and host age at the time of oviposition

The growth and development ofApanteles glomeratus L. eggs and larvae in the host larva (Pieris rapae crucivora Boisduval) was investigated by calculating their volume. WhenA. glomeratus eggs increase 90 fold in volume after being laid, larvae hatch from them. The larvae grow exponentially and the growth rate of the parasitoid is dependent on the host stage. Being laid in the 1st instar host, the parasitoids grow more slowly than those laid in 2nd–4th instar host. A pupal host stage prevents the parasitoids’ development. When larvae exceed the threshold size of 5.0×10⁸ μ³, they enter the 2nd instar. A few days after they attain the maximum size of 3.3×10⁹ μ³, they moult and egress from the host body.     

Development of Asian parasitoids in larvae Of Drosophila Suzukii feeding on blueberry and artificial diet

In just a few years, the Asian fly Drosophila suzukii has invaded several continents and has become a very serious pest of many fruit crops worldwide. Current control methods rely on chemical insecticides or expensive and labour‐intensive cultural practices. Classical biological control through the introduction of Asian parasitoids that have co‐evolved with the pest may provide a sustainable solution on condition that they are sufficiently specific to avoid non‐target effects on local biodiversity. Here, we present the first study on the development of three larval parasitoids from China and Japan, the Braconidae Asobara japonica and the Figitidae Leptopilina japonica and Ganaspis sp., on D. suzukii. The Asian parasitoids were compared with Leptopilina heterotoma, a common parasitoid of several Drosophilidae worldwide. The three Asian species were successfully reared on D. suzukii larvae in both, blueberry and artificial diet, in contrast to L. heterotoma whose eggs and larvae were encapsulated by the host larvae. All parasitoids were able to oviposit one day after emergence. Asobara japonica laid as many eggs in larvae feeding in blueberry as in artificial diet, whereas L. heterotoma oviposited more in larvae on the artificial diet and the Asian Figitidae oviposited more in larvae feeding on blueberry. Ganaspis sp. laid very few eggs in larvae in the artificial diet, suggesting that it may be specialized in Drosophila species living in fresh fruits. These data will be used for the development of a host range testing to assess the suitability of Asian parasitoids as biological control agents in invaded regions.     

Host-associated allozyme variation in tree cambium miners,Phytobia spp. (Diptera: Agromyzidae)

The larvae of the agromyzid flies that belong to the genus Phytobia Lioy feed by mining in the differentiating xylem just below the cambium of growing forest trees. The genus, which is apparently one of the most primitive groups in the Agromyzidae, comprises over 50 currently recognized species. Most of the species are mono- or oligophagous, and the host plants belong to numerous genera in about 60 families. Thus, Phytobia is an attractive candidate for studies on the evolution of insect-plant relationships. In spite of this, the taxonomy of Phytobia is currently poorly understood, mainly because the morphological differences between species are small. We used allozyme electrophoresis to investigate whether molecular markers could be used to separate and identify species in Phytobia, and to study the patterns of host use in the group. For this, we collected Phytobia larvae from eight host tree species occurring in southern Finland. An analysis of 10 variable allozyme loci showed that there are probably five species of Phytobia that feed on the hosts included in our study: one occurs on birches (Betula pubescens Ehrh. and B. pendula Roth) and alders (Alnus incana (L.) Moench and A. glutinosa (L.) Gaertn.), one on rowan (Sorbus aucuparia L.), and three species with overlapping feeding ranges on aspen (Populus tremula L.) and two willow species (Salix phylicifolia L. and S. caprea L.). Because birches and alders belong to the plant family Betulaceae, rowan to Rosaceae, and aspen and willows to Salicaceae, the host associations of the individual fly species can be explained by the taxonomic affinities of the hosts. However, our results also show that on a larger scale the evolution of host-plant associations in Phytobia cannot be explained by strict parallel cladogenesis (cospeciation) between the flies and their hosts.     

The influence of ants and water availability on oviposition behaviour and survivorship of a facultatively ant-tended herbivore

1. The lycaenid butterfly Hemiargus isola associates facultatively with the ant species Formica perpilosa in arid areas of south-western North America. Ants solicit liquid food rewards from butterfly larvae as larvae feed on the host plant, Acacia constricta . Previous studies have shown that tending by F. perpilosa enhances larval growth and pupal survivorship.
2. The effects of ants and plant water content on oviposition behaviour and survivorship to the last larval instar were tested by excluding ants and supplementing water to host plants in a two-way factorial experiment.
3. Butterflies, which lay eggs singly on host plant inflorescences, laid significantly higher egg numbers and densities (eggs/inflorescence) on plants with ants than on plants without ants. This is the first report of a facultative, generalized ant-associate using ants as oviposition cues. Water supplements increased the number, but not the density, of eggs laid on plants. Therefore, it appears that egg-laying butterflies responded to number of inflorescences, rather than plant tissue water per se .
4. Plants with ants had significantly greater numbers of inflorescences during the experiment than plants without ants. Water supplements increased number of inflorescences slightly, but not significantly.
5. Ants increased larval survivorship. Twice as many fourth-instar larvae survived per egg laid on plants with ants than on plants without ants. Ants did not reduce the number of predators present on acacias, but may have reduced predator effectiveness. Ants also did not reduce the numbers of potential H. isola competitors present.
6. Water supplementation affected neither the survivorship of H. isola larvae, nor the intensity of ant tending. Water supplementation did not affect the abundance of predators on plants, but did increase the abundance of several herbivorous insect taxa.     

Dependence on host constituents controlling food acceptance by Manduca sexta larvae

The host range of Manduca sexta L. (Lepidoptera: Sphingidae) is restricted in nature to plants in the family Solanaceae. However, naive hatchling larvae often accept and continue their development on foliage from a wide spectrum of unrelated plants. In contrast, solanaceous-experienced larvae refuse to feed on other plants. Experiments were designed to explore the role of constituents of various plants in this behavioral phenomenon. Fourth instar larvae reared on solanaceous hosts: tomato (Lycopersicon esculentum Mill.), potato (Solanum tuberosum L.), or tobacco (Nicotiana tabacum L.), and the leguminous non-host cowpea (Vigna sinensis Savi), or on artificial diet based on wheat germ were tested for their acceptance or preference when offered a new diet in both choice and no-choice situations. Under no-choice conditions, acceptability of cowpea foliage was strongly affected by the larval dietary experience. Most larvae reared on solanaceous foliage did not feed, whereas those larvae reared on non-solanaceous food readily accepted cowpea. Moreover, solanaceous foliage, leaf discs and extracts were readily accepted by larvae regardless of their dietary experience. Larvae reared on any of the solanaceous plants strongly preferred cowpea discs that were treated with solanaceous extract, while larvae reared on non-solanaceous diets did not discriminate between treated and control discs. Assays of cowpea extracts as well as acceptance of cowpea discs treated with solanaceous extract indicated a lack of detectable deterrent in cowpea. Our results suggest that the mechanism for induced host specificity in M. sexta larvae involves development of a dependence on solanaceous chemical constituents. We argue that this dependence on host plant chemistry has adaptive significance.     

Crepidula fornicata is not a first intermediate host for trematodes: who is?

Trematode larvae must generally invade a molluscan intermediate host, usually a gastropod, before they can reach reproductive maturity in another definitive host. The research literature to date has focused almost exclusively on the documented specificity between particular trematode species and particular molluscan hosts; little attention has been paid to gastropod species that do not appear to serve as hosts. We sampled Rhode Island and Massachusetts populations of the marine gastropod Crepidula fornicata to determine whether this widespread species serves as a first intermediate host for trematodes. We also sampled from the same habitat populations of Littorina littorea and Ilyanassa obsoleta, gastropods known to serve as first intermediate hosts for several trematode species. All individuals were examined by dissection for the presence of sporocysts, rediae, or developing cercariae. Although 4-28% of L. littorea (N=112) and I. obsoleta (N=84) were infected by larvae of at least one trematode species, no individuals of C. fornicata sampled from the same locations were so infected (N=136). A survey of the Biological Abstracts computer database indicates that snails in only about 10% of marine gastropod families are known to serve as first intermediate hosts for trematodes. We suggest that more attention be paid to marine gastropods that appear not to be infected by trematode miracidia. Such species may productively serve as new models for understanding trematode host specificity and gastropod resistance to infection.     

Synchronisation of adult activity of the archaic moth, <Emphasis Type="Italic">Micropterix calthella</Emphasis> L. (Lepidoptera,Micropterigidae), with anthesis of sedges (<Emphasis Type="Italic">Carex</Emphasis> spp., Cyperaceae) in an ancient wood

Micropterix calthella L. (Micropterigidae) is a small, day-flying moth from the basal-most extant lineage of the Lepidoptera. The species name reflects its conspicuous presence on Caltha palustris L. (Ranunculaceae). However, adults also favour sedges (Carex spp., Cyperaceae), on which they gather gregariously to feed on pollen and find mates. In a UK ancient wood, the phenology of eight sedge species together with individual moth and mating pair densities were monitored from 15th April to 8th June 2009. 4841 moth sightings were recorded. Moths on Carex spikes at various developmental stages were compared with null models to test for preference patterns. Approximately 99% of individuals selected Carex spikes where dehiscing anthers were present. The sedge phenology data suggest three distinct periods of pollen production. Overlaying this with the moth data reveals moth phenology strongly linked to a suite of early and mid-season woodland sedges. Of the twenty-eight other angiosperm species (seventeen families) in flower, only Ranunculus ficaria L. (Ranunculaceae) and R. repens L. attracted moths. Adult moths kept in captivity on potted Carex flacca Schreb. for 10 days laid eggs at the plant-soil interface. When C. flacca pollen production ceased, surviving adults were moved onto freshly dehiscing anthers of potted C. pallescens L., where they survived a further 14 days. Soil-dwelling first instar larvae were observed to consume C. sylvatica Huds leaves. In a choice experiment, larvae were significantly more likely to consume C. sylvatica than Stellaria media (L.) Vill. (Caryophyllaceae) leaf material (previously noted to be favoured by larvae). Synchrony between adult moths and Carex spp., and the use of Carex by both adults and larvae, suggests sedges may be host plants for M. calthella in lowland ancient woodlands.     

Biology of Larinus curtus Hochhut (Coleoptera: Curculionidae), a European Weevil for Biological Control of Yellow Starthistle Centaurea solstitialis L (Asteraceae), in the United States

The biology of the weevil Larinus curtus Hochhut was studied in the field in northern Greece and in the laboratory in Rome, Italy, and in Thermi, near Thessaloniki, Greece. The species is univoltine, and adults overwinter in ground litter. Eggs are inserted into the flowers of yellow starthistle (Centaurea solstitialis L.) where the larvae feed mainly on developing achenes, destroying on average over 96% of the seeds in infested flowerheads. Overwintered adults lived up to 84 days, females laid up to 70 eggs each, eggs hatched 4.2 ± 0.6 days after being laid, larvae required 17 to 20 days to develop through the four instars, and pupal development required 4 to 5 days under laboratory conditions. Six percent of 360 seedheads collected on July 13 and 28, 1988 were infested with L. curtus larvae and up to 89% of the larvae were parasitized. The species is recommended for the biological control of C. solstitialis in the United States.