Introduction of Beauveria bassiana as a biological control agent against the Ommatissus lybicus in Kerman province

Dubas bug, Ommatissus lybicus is one of the major sucking pests of date palm. Data palm is the most important economic crop in Iran. In this research, we isolated the pathogenic strain KB 201, KB 206, KB 211, KB 215, KB 220 and KB 512, of entomopathogenic fungi Beauveria bassiana from soil and insects, which produced aerial and submerged conidia and blastospores in the laboratory conditions. We investigated the best conditions for the production and utilisation of the spore suspension to spray the nymph of O. lybicus, which is one of the important pests in Kerman province (Iran). A total of 180 isolates that naturally infected by O. lybicus were collected from date palm in Kerman province during spring and summer seasons 2010–2011. The pathogen city test was carried out with direct spray. To bioassay the isolates, three concentrations of the spore suspension were prepared as follows: 1?×?10⁶, 1?×?10⁷ and 1?×?10⁸?conidia/ml. The pests were sprayed by aerial conidial suspension, which was prepared by 0.01% Tween 80 in distilled water, and the controls were sprayed by 0.01% Tween 80in distilled water. After spraying the pests, the plates were incubated at 25?±?1?°C and 80% of relative humidity. Then, the treated pests were monitored every day for the fungal growth and mortality.     

Field collection of egg parasitoids of Pentatomidae and Scutelleridae in Northwest Italy and their efficacy in parasitizing Halyomorpha halys under laboratory conditions

The invasion of Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) has caused severe economic damage in crops in North America and Europe, motivating research to identify its natural enemies, both in native and invaded areas. In its Asian native range, the main natural enemies are egg parasitoids, among which the most effective are Trissolcus japonicus (Ashmead) and Trissolcus mitsukurii (Ashmead) (Hymenoptera: Scelionidae) in China and Japan, respectively. In Europe, biology, host range, and impact of most native scelionid species are not well‐known. The present study aimed to investigate (1) presence and abundance of scelionid species that parasitize native Pentatomidae and Scutelleridae eggs in Northwest Italy, and (2) their ability to develop on H. halys eggs. During 4‐year field surveys, egg masses were collected and reared until bug nymph or adult parasitoid emergence. Then, the obtained scelionid females were tested for their ability to parasitize H. halys eggs in laboratory no‐choice experiments. Egg masses of all collected bug species were parasitized, and Telenomus spp. (Hymenoptera: Scelionidae), Trissolcus belenus (Walker), and Anastatus bifasciatus (Geoffroy) (Hymenoptera: Eupelmidae) were the most common parasitoids. In the laboratory, Trissolcus kozlovi Rjachovskij was the only species to significantly produce offspring from fresh H. halys eggs, whereas all tested Trissolcus species significantly induced host egg abortion (non‐reproductive effects). This study provides knowledge of the parasitoid species associated with native bugs, and represents a starting point to investigate the intricate interactions between native and exotic parasitoids recently found in northern Italy. These egg parasitoids could potentially be effective biocontrol agents of H. halys.     

Isolation and selection of virulent isolates of Beauveria bassiana for biological control of Ommatissus lybicus in Kerman province

Date palm (Phoenix dactylifera) is the most important economic crop in Kerman province. The palm date leafhopper (Ommatissus lybicus) is one of the most important and key pests that causes high level damage to date crop. Date is an organic fruit in this area, and biological control has been introduced as the best long-term strategy in this region. To investigate appropriate biological control agents in Kerman province during 2005–2007, 178 isolates were collected from naturally infected O. lybicus for the first time recorded in the world, and Beauveria bassiana was introduced as a suitable biological control agent for control of this pest.     

Effect of deltamethrin on the gills of Aphanius dispar: a microscopic study

Aphanius dispar, a freshwater fish (mean total length ± sd, 3.42 ± 0.33 cm) was exposed to different concentrations of deltamethrin (2.25, 2.50 and 3.00 μg L⁻¹), an insecticide used to control Dubas bug, Ommatissus lybicus in Oman. The histopathological changes in the structure of the gills in fish exposed to deltamethrin was studied using light, transmission and scanning electron microscopy. In light microscopy, the fish exposed to 2.25 μg L⁻¹ deltamethrin, showed hypertrophy and hyperplasia of chloride cells, while in 2.50 μg L⁻¹, additional changes like vacuolization, lifting of the lamellar epithelium and fusion of secondary lamellae were observed. The most severe alteration including vacuolization, desquamation of cells and dilation of intercellular space was recorded at 3.00 μg L⁻¹. Transmission and scanning electron microscopy, supports the findings of light microscopy and further document the ultrastructural damage caused, especially in exposure to 2.50 and 3.00 μg L⁻¹. Al l changes observed are described in detail. The deltamethrin exposure concentration of 2.25 μg L⁻¹ seems to be a threshold above which any small increase in concentration results in severe damage. All present results have been compared with those of previous studies on gill damage caused by various chemical substances. The impacts of the damage on the functioning of gills as a respiratory organ are discussed.     

Eggs Distribution Behaviour of Dubas Bug (Ommatissus Lybicus: Homoptera: Tropiduchidae) in Relation to Seasons and Some Physico- Morphic Characters of Date Palm Leaves

Dubas bug, Ommatissus lybicus, is a major pest of date palm in Panjgur Balochistan. Both the nymphs and adults suck the sap from fruit stalk, leaves and may cause about 50 % of economic losses. Chlorophyll contents and leaf thickness was measured by using SPAD-502 chlorophyll meter and vernier caliper respectively. Eggs distribution density was highly significant in different frond rows and within frond during spring (1^st) and summer (2^nd) generations. In both generations number of eggs per leaflet decreased towards the apex fronds rows and within frond number of eggs decreased towards the terminal leaflets. Eggs distribution had negative correlation with leaf thickness; chlorophyll contents (SPAD value) and frond row (bottom to top). Apparently shade affect the eggs laying behaviour of dubas bug.     

Efficacy of commercially available predators,nematodes and fungal entomopathogens for augmentative control of Drosophila suzukii

The recent arrival of Drosophila suzukii, an invasive pest of soft‐skinned fruit with a wide host range, has resulted in increased production costs for growers and the need for additional insecticide applications each growing season. There are few effective organic insecticides for D. suzukii, and insecticide use in conventional farms may be disruptive to natural enemies, suggesting a need for effective biological control to combat D. suzukii. Commercially available natural enemies were evaluated for their potential use in augmentative releases, including: the predators Orius insidiosus and Dalotia coriaria; the entomopathogenic fungi Metarhizium anisopliae, Beauveria bassiana and Paecilomyces fumosoroseus; and the entomopathogenic nematodes Heterorhabditis bacteriophora, Steinernema feltiae and S. carpocapsae. This suite of natural enemies was chosen to target D. suzukii adults as well as larvae in hanging or dropped fruit. Of the cultured fungal strains tested, only M. anisopliae significantly decreased D. suzukii survival, but it had low residual activity and no effect on D. suzukii fecundity. O. insidiosus decreased D. suzukii survival in simple laboratory arenas but not on potted blueberries or bagged blueberry branches outdoors. D. coriaria did not decrease D. suzukii survival in infested blueberries in simple laboratory arenas. The nematodes tested showed low infection rates and were not able to affect D. suzukii survival. Although this suite of natural enemies showed limited ability to suppress D. suzukii under the tested conditions, these and related natural enemies are present as part of the endemic natural enemy community in agricultural fields, where they may contribute to D. suzukii suppression.     

Unrelated facultative endosymbionts protect aphids against a fungal pathogen

The importance of microbial facultative endosymbionts to insects is increasingly being recognized, but our understanding of how the fitness effects of infection are distributed across symbiont taxa is limited. In the pea aphid, some of the seven known species of facultative symbionts influence their host's resistance to natural enemies, including parasitoid wasps and a pathogenic fungus. Here we show that protection against this entomopathogen, Pandora neoaphidis, can be conferred by strains of four distantly related symbionts (in the genera Regiella, Rickettsia, Rickettsiella and Spiroplasma). They reduce mortality and also decrease fungal sporulation on dead aphids which may help protect nearby genetically identical insects. Pea aphids thus obtain protection from natural enemies through association with a wider range of microbial associates than has previously been thought. Providing resistance against natural enemies appears to be a particularly common way for facultative endosymbionts to increase in frequency within host populations.     

Contributions of climate,plant phenology and natural enemies to the seasonal variation of aphids on cabbage

Brevicoryne brassicae (L), Lipaphis erysimi (Kalt) and Myzus persicae (Sultzer) (Homoptera: Aphididae) form the aphid complex that causes great losses in Brassicaceae in tropical and subtropical regions. Knowledge of their population dynamics is important for the development of integrated pest management programmes. This study aimed to investigate the effects of cabbage phenology, climatic factors and natural enemies populations on the dynamics of these organisms, and the factors regulating their predators’ occurrence. The densities of aphids and their natural enemies and the climate were monitored for two years in 16 cabbage crops. The highest densities of the aphids occurred during periods of relative humidity (RH) drop, a condition that affects them positively. Regarding the predators, the factors affecting their abundance varied but RH was positively related to most of them. This study provides relevant insights into the factors that regulate the aphids in cabbage and for the decision‐making process of control of these severe pests.     

Comparative study of development parameters of four Ooencyrtus spp. (Hymenoptera: Encyrtidae) on natural and factitious hosts

Biological control approaches such as seeding and augmentation releases of populations of natural enemies mostly rely on the indoor production of predator or parasitoid species, often with the use of alternative prey/host species. In this study, we investigated several development parameters of four egg parasitoid species: Ooencyrtus fecundus, O. near fecundus, O. pityocampae and O. telenomicida, and compared their performance on their natural host, the variegated caper bug (CB) Stenozygum coloratum, and on an alternative, factitious host, the silk moth (SM) Bombyx mori. Survival was higher and development duration shorter in CB eggs, making the CB a better host for these congeners. However, adult longevity was generally longer for individuals that developed in SM eggs. Moreover, O. fecundus and O. pityocampae females that had developed in SM eggs displayed higher fecundity than all other female/host combinations. Survival also varied according to the age of the SM eggs: parasitoid survival rates were significantly higher in 9‐ to 12‐month‐old (post‐diapausing) eggs than in young (about 1 month old) ones. These results were probably influenced by differences among the egg sizes of the studied hosts. The number of non‐laying females and self‐superparasitism rates were exceptionally high in O. near fecundus. These findings suggest that SM eggs, and especially those which are being utilized after a long storage, could serve for mass rearing of the studied Ooencyrtus spp.     

Irukandji jellyfish polyps exhibit tolerance to interacting climate change stressors

Increasing ocean temperatures and strengthening boundary currents have caused the poleward migration of many marine species. Cubozoan jellyfish known to cause Irukandji syndrome have historically been confined to tropical waters but may be expanding into subtropical regions. Here, we examine the interactive effects of warming and acidification on the population dynamics of polyps of an Irukandji jellyfish, Alatina nr mordens, and the formation of statoliths in newly metamorphosed medusae, to determine if this jellyfish could tolerate future conditions predicted for southeast Queensland (SEQ), Australia. Two experiments, examining the orthogonal factors of temperature and pH, were undertaken. Experiment 1 mimicked the current, ca. 2050 and ca. 2100 summer temperature and pH conditions predicted for SEQ using A1F1 scenarios (temperature: 25, 27, 29 °C; pH: 7.9, 7.8, 7.6) and Experiment 2 mimicked current and future winter conditions (18 and 22 °C, pH 7.9, 7.8, 7.6). All polyps in Experiment 1 survived and budded. Fewer polyps budded in the lower pH treatments; however, patterns varied slightly among temperature treatments. Statoliths at pH 7.6 were 24% narrower than those at pH 7.8 and 7.9. Most polyps survived the winter conditions mimicked by Experiment 2 but only polyps in the 22 °C, pH 7.9 treatment increased significantly. The current absence of A. nr mordens medusae in SEQ, despite the polyps' ability to tolerate the current temperature and pH conditions, suggests that ecological, rather than abiotic factors currently limit their distribution. Observations that budding was lower under low pH treatments suggest that rates of asexual reproduction will likely be much slower in the future. We consider that A. nr mordens polyps are likely to tolerate future conditions but are unlikely to thrive in the long term. However, if polyps can overcome potential ecological boundaries and acidification proceeds slowly A. nr mordens could expand polewards in the short term.     

Bioecology of some key cashew insect pests and diseases in diverse habitats and landscapes in Tanzania

Cashew (Anacardium occidentale) is an economically important cash crop for many rural households in Tanzania. However, its production is constrained by some insect pests and diseases. As a prerequisite for the development of a more sustainable integrated insect pest and disease management strategy for cashew, information on the biology and ecology of the key insect pests and diseases in a changing environment, and on influencing biotic and abiotic factors, is needed. Surveys were conducted in the major cashew nut‐producing areas of Tanzania for two seasons: August to December, 2009, and August to December, 2010. Data on number of infested and infected shoots by key insect pests and diseases, natural enemies and associated farmer practices, namely synthetic pesticide use and intercropping systems, were collected from different subzones within agroecological zones. Our data showed that abundance and diversity of key cashew insect pests and diseases were influenced by agroecological zones and subzones. Intercropping was more commonly practised in the northern than in the southern zone. Agrochemicals were most frequently used in the southern agroecological zone and affected the occurrence of natural enemies, notably the weaver ant that was more abundant in the northern zone. Furthermore, our findings revealed that Helopeltis sp. and the powdery mildew remained the major constraints to cashew nut production in Tanzania.     

Survival of a specialist natural enemy experiencing resource competition with an omnivorous predator when sharing the invasive prey Tuta absoluta

Can specialist natural enemies persist in ecosystems when competing with omnivorous natural enemies for their shared prey? The consequences of omnivory have been studied theoretically, but empirical studies are still lacking. Omnivory is nevertheless common in nature and omnivorous predators coexist with specialists in many ecosystems, even when they are intraguild predators. This type of association is also common in agroecosystems in which biological control strategies are used. Our study provides an example of the outcome of such an association in the context of biological control of the invasive pest Tuta absoluta (Lepidoptera) in a tomato agroecosystem. The two natural enemies involved, that is, a specialist (Stenomesius japonicus (Hymenoptera) parasitoid) and an omnivore (Macrolophus pygmaeus (Hemiptera) predator), were able to coexist for 3 months in our experimental cages in the absence of metacommunity mechanisms (i.e., emigration and recolonization), contrary to theoretical expectations. However, they negatively affected each other's population dynamics. We found that spatial resource segregation was not a mechanism that promoted their coexistence. Regarding pest control, the specialist and omnivorous natural enemies were found to exhibit complementary functional traits, leading to the best control when together. Mechanisms that may have promoted the coexistence of the two species as well as consequences with regard to the inoculative biological control program are discussed.     

Combining lacewings and parasitoids for biological control of foxglove aphids in sweet pepper

The role of natural enemy diversity in biological pest control has been debated in many studies, and understanding how interactions amongst predators and parasitoids affect herbivore populations is crucial for pest management. In this study, we assessed the individual and combined use of two species of natural enemies, the parasitoid Aphidius ervi Haliday, and the predatory brown lacewing Micromus variegatus (Fabricius), on their shared prey, the foxglove aphid, Aulacorthum solani (Kaltenbach), on sweet pepper. We hypothesized that the presence of intraguild predation (IGP) and predator facilitation (through induced aphid dropping behaviour) might have both negative and positive effects on aphid control, respectively. Our greenhouse trial showed that overall, the greatest suppression of aphids occurred in the treatment with both the parasitoid and the lacewing. While the combination of lacewings and parasitoids significantly increased aphid control compared to the use of parasitoids alone, the effect was not significantly different to the treatment with only predators, although there was a clear trend of enhanced suppression. Thus, the combined effects of both species of natural enemies were between additive and non‐additive, suggesting that the combination is neither positive nor negative for aphid control. High levels of IGP, as proven in the laboratory, were probably compensated for by the strong aphid suppression provided by the lacewings, whether or not supplemented with some level of predator facilitation. For aphid management over a longer time scale, it might still be useful to combine lacewings and parasitoids to ensure stable and resilient aphid control.     

Bacillus thuringiensis plants expressing Cry1Ac,Cry2Ab and Cry1F are not toxic to the assassin bug,Zelus renardii

Cotton‐ and maize‐producing insecticidal crystal (Cry) proteins from the bacterium, Bacillus thuringiensis (Bt), have been commercialized since 1996. Bt plants are subjected to environmental risk assessments for non‐target organisms, including natural enemies that suppress pest populations. Here, we used Cry1F‐resistant Spodoptera frugiperda (J.E. Smith) and Cry1Ac and Cry2Ab‐resistant Trichoplusia ni (Hübner) as prey for the assassin bug, Zelus renardii (Kolenati), a common predator in maize and cotton fields. In tritrophic studies, we assessed several fitness parameters of Z. renardii when it fed on resistant S. frugiperda that had fed on Bt maize expressing Cry1F or on resistant T. ni that had fed on Bt cotton expressing Cry1Ac and Cry2Ab. Survival, nymphal duration, adult weight, adult longevity and female fecundity of Z. renardii were not different when they were fed resistant‐prey larvae (S. frugiperda or T. ni) reared on either a Bt crop or respective non‐Bt crops. ELISA tests demonstrated that the Cry proteins were present in the plant at the highest levels, at lower levels in the prey and at the lowest levels in the predator. While Z. renardii was exposed to Cry1F and Cry1Ac and Cry2Ab when it fed on hosts that consumed Bt‐transgenic plants, the proteins did not affect important fitness parameters in this common and important predator.     

Host plant volatiles responsible for the invasion of Stenotus rubrovittatus (Heteroptera: Miridae) into paddy fields

We investigated the attractiveness of synthetic volatile blends or individual volatiles of flowering rice panicles or flowering Scirpus juncoides spikelets to the sorghum plant bug Stenotus rubrovittatus (Matsumura). None of the individual chemicals tested attracted either sex of the bug. Synthetic volatile blends of flowering rice panicles composed of geranyl acetone, β‐caryophyllene, n‐decanal, methyl salicylate, β‐elemene and n‐tridecene attracted females. The synthetic blend of volatiles was just as attractive as natural flowering rice panicles to females. Other synthetic blends did not attract the bug. We sampled headspace volatiles from flowering S. juncoides spikelets with solid‐phase microextraction and analysed them using gas chromatography–mass spectrometry. The main volatile emitted from S. juncoides was β‐caryophyllene, one of the major volatile components of flowering rice panicles. β‐Elemene was a common volatile found in flowering rice panicles and flowering S. juncoides spikelets. Therefore, we investigated the attractiveness of synthetic blends of flowering rice panicles and S. juncoides spikelets composed of β‐caryophyllene and β‐elemene. The synthetic blend of flowering S. juncoides spikelets significantly attracted males but not females. The synthetic blend of flowering rice panicles composed of β‐caryophyllene and β‐elemene did not attract either sex. These results suggest that β‐caryophyllene and β‐elemene are common active compounds responsible for attractiveness of flowering rice panicles and S. juncoides spikelets although some of the other volatile components act synergistically with these two compounds in natural plant odours.     

Dietary specialization and the effects of plant species on potential multitrophic interactions of three species of nymphaline caterpillars

The diet breadth of insect herbivores influences their response to variation in plant quality, and these bitrophic interactions have implications for the higher‐level trophic interactions between herbivores and their natural enemies. In this comparative study, we examined the role of host plant species and plant secondary chemistry on the potential interactions between three species of nymphaline caterpillars and their natural enemies. The caterpillar species (all Lepidoptera: Nymphalidae) varied in their degree of specialization: the buckeye, Junonia coenia Hübner, is a specialist on plants that contain iridoid glycosides (IGs); the white peacock, Anartia jatrophae L., feeds on plants in five families, some of which contain IGs and some of which do not; and the painted lady, Vanessa cardui L., is a generalist, feeding on plants in at least 15 families. Each species was reared on leaves of an introduced host plant, Plantago lanceolata L. (Plantaginaceae), which produces two IGs, aucubin and catalpol, and on another plant species that is a common host plant. These alternate host plants were Plantago major L. (Plantaginaceae) for J. coenia, Bacopa monnieri (L.) Pennell (Plantaginaceae) for A. jatrophae, and Malva parviflora L. (Malvaceae) for V. cardui. We examined growth, sequestration, and immune response of these caterpillars on the different host plant species. Junonia coenia developed more rapidly and sequestered higher IG concentrations when reared on P. lanceolata, whereas both other species grew more slowly on P. lanceolata. Host plant did not influence immune response of J. coenia or A. jatrophae, whereas V. cardui immune response was weaker when reared on P. lanceolata. Junonia coenia was most efficient at IG sequestration and A. jatrophae was least efficient, when all three species were reared on P. lanceolata. These results indicate that diet breadth may play an important role in structuring tritrophic interactions, and this role should be further explored.     

Phorid species from Acromyrmex’s hosts and effect on their survival of two fungi proposed for the control of leafcutter ants

Phorid flies (Diptera: Phoridae, Metopinini) are natural enemies of leafcutter ants (Hymenoptera: Formicidae, Attini), which are among the most important pests in the Neotropical region. These parasitoids lay their eggs inside worker ants, causing the death of the parasitized ants, and the oviposition attacks on foraging workers interfere with the collection of vegetal material used in fungal gardens, thereby affecting the whole colony. However, because of the large number of ants per colony, more than one type of biological control agent is needed to have a significant impact. We collected parasitized leafcutter ants Acromyrmex lundii (Guérin‐Méneville), Acromyrmex heyeri (Forel), and Acromyrmex ambiguus (Emery) from various places in Argentina and reared their parasitoids. We recorded developmental times, host and phorid sizes, and other aspects of the biology of the phorids Apocephalus neivai Borgmeier, Apocephalus noetingerorum Brown & Disney, Myrmosicarius gracilipes Borgmeier, Myrmosicarius catharinensis Borgmeier, Myrmosicarius crudelis Borgmeier, and Myrmosicarius cristobalensis Disney et al. This is the first record of A. ambiguus, an important pest of pine plantations, being a host of phorids. We found the first cases of gregarious parasitoidism of a parasitoid with no‐free pupae: M. catharinensis on A. lundii ants. We also evaluated the effect on pupal survival of two cosmopolitan fungi, Beauveria bassiana (Balsamo) Vuill. and Trichoderma lentiforme (Rehm) Chaverri et al., which are also considered as potential biological control agents of leafcutter ants. Suspensions of conidia were tested on Myrmosicarius and Apocephalus parasitoid pupae of different ages. No negative effect on pupal survival was found under either fungal treatment. Therefore, the use of both natural enemies separately but simultaneously, or the introduction of fungi‐inoculated pupae in the pest habitats, seems to be a promising strategy for the multiple biological control of leafcutter ants.     

Effect of resistant and susceptible soybean cultivars on the attraction of egg parasitoids under field conditions

The association of resistant crop varieties and biological pest control has great potential for pest management, as resistant cultivars may affect herbivore population dynamics by interfering with their biology and search behaviour for host plants. In addition, resistant varieties can also affect the efficiency of natural enemies. The aims of this work were to evaluate the influence of the soybean cultivars Dowling (resistant), IAC 100 (resistant) and Silvânia (susceptible) under field conditions on: (i) the abundance of parasitoids in the Platygastridae family and the stink bug Euschistus heros and (ii) the parasitism of stink bug eggs by these natural enemies. There was no difference between cultivars in stink bug distribution in the field. The parasitoids Telenomus podisi, Trissolcus teretis, Tr. urichi and Tr. brochymenae emerged from the sentinel eggs of E. heros, and T. podisi was the most abundant species observed during the reproductive stage R6. The cultivars Dowling and IAC 100 attracted a higher number of Platygastridae parasitoids, T. podisi and Tr. teretis, and the abundance of these parasitoids during the period from R1 to R7 might have being sufficient to control the stink bug population. These results suggest that the cultivars Dowling and IAC 100 have important attributes that should be taken into account in the implementation and development of new cultivars in breeding programmes that aim to obtain plants more resistant to stink bugs and more attractive to natural enemies.     

Length polymorphisms at two candidate genes explain variation of migratory behaviors in blackpoll warblers (Setophaga striata)

Migratory behaviors such as the timing and duration of migration are genetically inherited and can be under strong natural selection, yet we still know very little about the specific genes or molecular pathways that control these behaviors. Studies in candidate genes Clock and Adcyap1 have revealed that both of these loci can be significantly correlated with migratory behaviors in birds, though observed relationships appear to vary across species. We investigated geographic genetic structure of Clock and Adcyap1 in four populations of blackpoll warblers (Setophaga striata), a Neotropical–Nearctic migrant that exhibits geographic variation in migratory timing and duration across its boreal breeding distribution. Further, we used data on migratory timing and duration, obtained from light‐level geolocator trackers to investigate candidate genotype–phenotype relationships at the individual level. While we found no geographic structure in either candidate gene, we did find evidence that candidate gene lengths are correlated with five of the six migratory traits. Maximum Clock allele length was significantly and negatively associated with spring arrival date. Minimum Adcyap1 allele length was significantly and negatively associated with spring departure date and positively associated with fall arrival date at the wintering grounds. Additionally, we found a significant interaction between Clock and Adcyap1 allele lengths on both spring and fall migratory duration. Adcyap1 heterozygotes also had significantly shorter migration duration in both spring and fall compared to homozygotes. Our results support the growing body of evidence that Clock and Adcyap1 allele lengths are correlated with migratory behaviors in birds.     

Asymmetrical intraguild predation between natural enemies of the citrus mealybug

The ability of a predator to discriminate against parasitized prey determines the extent of asymmetrical intraguild predation, which is often crucial for the outcome of biological control. Anagyrus nr. pseudococci (Girault) (Hymenoptera: Encyrtidae), a parasitoid of the citrus mealybug, Planococcus citri (Risso) (Hemiptera: Pseudococcidae), suffers from intraguild predation by coccinellids occurring in the same habitat. The level of intraguild predation on A. nr. pseudococci by Nephus includens (Kirsch) (Coleoptera: Coccinellidae) at different immature stages has been investigated with and without simultaneous offer of extraguild prey. Larvae of A. nr. pseudococci appeared to face increased intraguild predation at early developmental stages, whereas mummification provided adequate protection against the predatory coccinellid. Different predation levels on unparasitized vs. parasitized hosts at various developmental stages in choice assays indicated that N. includens preferences might be determined not solely by palatability of the prey but also by its ability to protect itself.