Spatial distribution of colonizing Listronotus maculicollis populations: implications for targeted management and host preference

We characterized the spatio‐temporal distribution of emerging overwintered adult Listronotus maculicollis populations colonizing golf course fairways with Spatial Analyses by Distance IndicEs (SADIE) with the goal to better target management tactics and to test assumptions for weevil preference for annual bluegrass (Poa annua). Adults randomly colonized and moved throughout fairways. However, cumulative captures were significantly aggregated along fairway edges closest to overwintering sites demonstrating progressive movement through the edges. Spatial association analyses suggest that the spatial patterns of cumulative captures of adults rather than weekly patterns were strongly associated with larvae, indicating that the adults enter fairways from the edges and deposit eggs over the course of several weeks. We did not observe an effect of host species on the distribution of either adult or larval L. maculicollis which leads us to question traditional assumptions of host preference for short mown P. annua. Instead, we propose that the aggregated distribution of larvae is generated by a low encounter rate of short mown hosts, rather than preference for species or cultivar. This study indicates that caution need to be applied when using preference‐performance criteria in host preference studies. Future behavioural studies need to address the contributions of encounter rate and host species on L. maculicollis host selection and oviposition.     

Ovipositional preferences and larval survival of annual bluegrass weevil,Listronotus maculicollis,on Poa annua and selected bentgrasses (Agrostis spp.)

The annual bluegrass weevil (ABW), Listronotus maculicollis Kirby (Coleoptera: Curculionidae), is a serious and expanding pest of short‐cut turfgrass on golf courses in eastern North America. Increasing problems with the development of insecticide resistance in this pest highlights the need for more sustainable management approaches. Plant resistance is one of the most promising alternative strategies. Bentgrasses are the dominant grass species on golf course fairways, tees, and putting greens in the areas affected by ABW. But Poa annua L. (Poaceae), a highly invasive weed, often constitutes a large percentage of turf stands in short‐mown golf courses and is thought to be particularly susceptible to ABW. We studied resistance to ABW in four cultivars of creeping bentgrass, Agrostis stolonifera L., and two cultivars each of colonial bentgrass, Agrostis capillaris L., and velvet bentgrass, Agrostis canina L. (Poaceae), in comparison with P. annua by addressing the three major components of resistance: antixenosis (adult ovipositional and feeding preferences), antibiosis (larval survival and growth), and grass tolerance (grass damage). Our findings suggest that antixenosis/non‐preference is at least partially involved in bentgrass resistance to ABW. Even though oviposition was observed in all tested grasses, females laid significantly fewer eggs in Agrostis spp. than in P. annua. Compared to P. annua, Agrostis spp. were also less suitable for larval development with lower numbers of ABW immatures recovered and larvae weighing less and being less advanced in development. Resistance levels to ABW larvae varied significantly among Agrostis spp. and cultivars. Agrostis canina was least preferred by females for oviposition and A. stolonifera was the least suitable for larval survival and development. Agrostis spp., especially A. stolonifera, were more tolerant to ABW feeding than P. annua. Our findings suggest that reduction in P. annua and replacement with Agrostis spp., especially A. stolonifera, wherever feasible should be integral to more sustainable approaches to ABW management.     

Interaction of Anthonomus grandis and cotton genotypes: biological and behavioral responses

The boll weevil, Anthonomus grandisBoheman (Coleoptera: Curculionidae), is a key pest of cotton, Gossypium hirsutumL. (Malvaceae). Knowledge about boll weevil feeding and oviposition behavior and its response to plant volatiles can underpin our understanding of host plant resistance, and contribute to improved monitoring and mass capture of this pest. Boll weevil oviposition preference and immature development in four cotton genotypes (CNPA TB90, TB85, TB15, and BRS Rubi) were investigated in the laboratory and greenhouse. Volatile organic compounds (VOCs) produced by TB90 and Rubi genotypes were obtained from herbivore‐damaged and undamaged control plants at two phenological stages – vegetative (prior to squaring) and reproductive (during squaring) – and four collection times – 24, 48, 72, and 96 h following herbivore damage. The boll weevil exhibited similar feeding and oviposition behavior across the four tested cotton genotypes. The chemical profiles of herbivore‐damaged plants of both genotypes across the two phenological stages were qualitatively similar, but differed in the amount of volatiles produced. Boll weevil response to VOC extracts was studied using a Y‐tube olfactometer. The boll weevil exhibited similar feeding and oviposition behavior at the four tested cotton genotypes, although delayed development and production of smaller adults was found when fed TB85. The chemical profile of herbivore‐damaged plants of both genotypes at the two phenological stages and time periods (24–96 h) was similar qualitatively, with 30 identified compounds, but differed in the amount of volatiles produced. Additionally, boll weevil olfactory response was positive to herbivory‐induced volatiles. The results help to understand the interaction between A. grandis and cotton plants, and why it is difficult to obtain cotton genotypes possessing constitutive resistance to this pest.     

Local and neighboring patch conditions alter sex‐specific movement in banana weevils

Understanding the mechanisms underlying the movements and spread of a species over time and space is a major concern of ecology. Here, we assessed the effects of an individual's sex and the density and sex ratio of conspecifics in the local and neighboring environment on the movement probability of the banana weevil, Cosmopolites sordidus. In a “two patches” experiment, we used radiofrequency identification tags to study the C. sordidus movement response to patch conditions. We showed that local and neighboring densities of conspecifics affect the movement rates of individuals but that the density‐dependent effect can be either positive or negative depending on the relative densities of conspecifics in local and neighboring patches. We demonstrated that sex ratio also influences the movement of C. sordidus, that is, the weevil exhibits nonfixed sex‐biased movement strategies. Sex‐biased movement may be the consequence of intrasexual competition for resources (i.e., oviposition sites) in females and for mates in males. We also detected a high individual variability in the propensity to move. Finally, we discuss the role of demographic stochasticity, sex‐biased movement, and individual heterogeneity in movement on the colonization process.     

Trichobaris weevils distinguish amongst toxic host plants by sensing volatiles that do not affect larval performance

Herbivorous insects use plant metabolites to inform their host plant selection for oviposition. These host‐selection behaviours are often consistent with the preference–performance hypothesis; females oviposit on hosts that maximize the performance of their offspring. However, the metabolites used for these oviposition choices and those responsible for differences in offspring performance remain unknown for ecologically relevant interactions. Here, we examined the host‐selection behaviours of two sympatric weevils, the Datura (Trichobaris compacta) and tobacco (T. mucorea) weevils in field and glasshouse experiments with transgenic host plants specifically altered in different components of their secondary metabolism. Adult females of both species strongly preferred to feed on D. wrightii rather than on N. attenuata leaves, but T. mucorea preferred to oviposit on N. attenuata, while T. compacta oviposited only on D. wrightii. These oviposition behaviours increased offspring performance: T. compacta larvae only survived in D. wrightii stems and T. mucorea larvae survived better in N. attenuata than in D. wrightii stems. Choice assays with nicotine‐free, JA‐impaired, and sesquiterpene‐over‐produced isogenic N. attenuata plants revealed that although half of the T. compacta larvae survived in nicotine‐free N. attenuata lines, nicotine did not influence the oviposition behaviours of both the nicotine‐adapted and nicotine‐sensitive species. JA‐induced sesquiterpene volatiles are key compounds influencing T. mucorea females’ oviposition choices, but these sesquiterpenes had no effect on larval performance. We conclude that adult females are able to choose the best host plant for their offspring and use chemicals different from those that influence larval performance to inform their oviposition decisions.     

Reducing boll weevil populations by clipping terminal buds and removing abscised fruiting bodies

Cotton pests damaging fruiting bodies (squares and young bolls) are difficult to control and their damage results in direct yield loss. Small growers, with low technological inputs, represent a large portion of cotton growers worldwide comprising more than 76 countries; they rely mainly on cultural practices to counteract pest attack in their crops. Boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae), oviposition involves puncturing cotton squares and young bolls, causing abscission. We examined the impact on boll weevil population of collecting abscised cotton fruiting bodies and clipping plant terminals at 50% boll maturation in the field during two cotton‐growing seasons and under field cage conditions. Greatest numbers of damaged squares occurred ca. 117 days after planting and clipped plants resulted in reduction of abscised structures and adult boll weevils compared with non‐clipped plants, irrespective of cotton variety. Damaged young bolls were found ca. 128 days after planting in 2009 and 2011, but clipping had no effect. Numbers of boll weevils found in plants of the varieties BRS 201 and BRS Rubi (both in 2009) and BRS Rubi (in 2011) were, respectively, 13‐, 17‐, and 20‐fold greater when clipping plus collecting abscised fruiting bodies were not practiced. Furthermore, the average percentage of the boll weevil parasitoid Bracon vulgaris Ashmead (Hymenoptera: Braconidae) emerging from abscised and collected structures was similar between clipped and non‐clipped plant terminals in both seasons. Clipping plant terminals did not result in yield reduction and reduced adult boll weevil production. Collecting abscised reproductive structures, clipping plant terminals, and using both practices together reduced boll weevil populations by as much as 63, 57, and 79%, respectively, in cage trials. Thus, these practices cause significant impact on boll weevil populations and are feasible of adoption, especially for smallholder cotton growers.     

Oviposition site preference and developmental performance of a gall‐inducing leafhopper on galled and non‐galled host plants

Oviposition preferences of herbivorous insects affect offspring performance. Both positive and negative links between oviposition preference and offspring performance have been reported for many species. A gall‐inducing leafhopper, Cicadulina bipunctata Melichar (Hemiptera: Cicadellidae), feeds on various Poaceae plants and induces galls of enhanced nutritional value for their offspring. Although gall induction by C. bipunctata improves nymphal performance, the oviposition preference of females between galled and non‐galled host plants is still unclear. In this paper, the nymphal performance and oviposition and feeding‐site preference of C. bipunctata were investigated using galled wheat, Triticum aestivum L., and non‐galled barley, Hordeum vulgare L., as host plants. The survival rate of C. bipunctata on wheat was significantly higher than on barley. In the choice test, significantly more eggs were laid into barley, whereas the number of eggs deposited on both hosts was not significantly different in the no‐choice test. The number of settling individuals per leaf area was not significantly different between wheat and barley, suggesting no clear preference for oviposition between these plants. Experience as a nymph with a growing host did not affect oviposition preference as adult female. The inconsistent correspondence between offspring performance and oviposition preference of C. bipunctata may reflect the high mobility of nymphs and/or differences in leaf area between host plants. The results indicate that the previous finding that oviposition preference and offspring performance are not always positively correlated in herbivorous insects is applicable to gall‐inducing insects.     

Maternal behaviours may explain riffle‐scale variations in some stream insect populations

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Host‐associated genomic differentiation in congeneric butterflies: now you see it,now you do not

Ecotypic variation among populations may become associated with widespread genomic differentiation, but theory predicts that this should happen only under particular conditions of gene flow, selection and population size. In closely related species, we might expect the strength of host‐associated genomic differentiation (HAD) to be correlated with the degree of phenotypic differentiation in host‐adaptive traits. Using microsatellite and Amplified Fragment Length Polymorphism (AFLP) markers, and controlling for isolation by distance between populations, we sought HAD in two congeneric species of butterflies with different degrees of host plant specialization. Prior work on Euphydryas editha had shown strong interpopulation differentiation in host‐adapted traits, resulting in incipient reproductive isolation among host‐associated ecotypes. We show here that Euphydryas aurinia had much weaker host‐associated phenotypic differentiation. Contrary to our expectations, we detected HAD in Euphydryas aurinia, but not in E. editha. Even within an E. aurinia population that fed on both hosts, we found weak but significant sympatric HAD that persisted in samples taken 9 years apart. The finding of significantly stronger HAD in the system with less phenotypic differentiation may seem paradoxical. Our findings can be explained by multiple factors, ranging from differences in dispersal or effective population size, to spatial variation in genomic or phenotypic traits and to structure induced by past histories of host‐adapted populations. Other infrequently measured factors, such as differences in recombination rates, may also play a role. Our result adds to recent work as a further caution against assumptions of simple relationships between genomic and adaptive phenotypic differentiation.     

Oviposition and larval development of a stem borer,Eoreuma loftini,on rice and non‐crop grass hosts

A greenhouse study compared oviposition preference and larval development duration of a stem borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), on rice, Oryza sativa L. cv Cocodrie (Poaceae), and four primary non‐crop hosts of Texas Gulf Coast rice agroecosystems. Rice and two perennials, johnsongrass, Sorghum halepense (L.) Pers., and vaseygrass, Paspalum urvillei Steud. (both Poaceae), were assessed at three phenological stages. Two spring annuals, brome, Bromus spec., and ryegrass, Lolium spec. (both Poaceae), were assessed at two phenological stages. Phenological stages represented the diversity of plant development stages E. loftini may encounter. Plant fresh biomass, dry biomass, and sum of tiller heights were used as measures of plant availability. Accounting for plant availability, rice was preferred over non‐crop hosts, and intermediate and older plants were preferred over young plants. Johnsongrass and vaseygrass were 32–60% as preferred as rice when considering the most preferred phenological stages of each host. Brome and ryegrass received few or no eggs, respectively. Eoreuma loftini larval development (in degree days above developmental threshold temperatures) was fastest on rice and slowest on johnsongrass and vaseygrass. Development duration was only retarded by plant stage on young rice plants. Foliar and stem free amino acid concentrations were determined to help provide insights on the mechanisms of E. loftini oviposition preference and developmental performance.     

Biogeography and host‐related factors trump parasite life history: limited congruence among the genetic structures of specific ectoparasitic lice and their rodent hosts

Parasites and hosts interact across both micro‐ and macroevolutionary scales where congruence among their phylogeographic and phylogenetic structures may be observed. Within southern Africa, the four‐striped mouse genus, Rhabdomys, is parasitized by the ectoparasitic sucking louse, Polyplax arvicanthis. Molecular data recently suggested the presence of two cryptic species within P. arvicanthis that are sympatrically distributed across the distributions of four putative Rhabdomys species. We tested the hypotheses of phylogeographic congruence and cophylogeny among the two parasite lineages and the four host taxa, utilizing mitochondrial and nuclear sequence data. Despite the documented host‐specificity of P. arvicanthis, limited phylogeographic correspondence and nonsignificant cophylogeny was observed. Instead, the parasite–host evolutionary history is characterized by limited codivergence and several duplication, sorting and host‐switching events. Despite the elevated mutational rates found for P. arvicanthis, the spatial genetic structure was not more pronounced in the parasite lineages compared with the hosts. These findings may be partly attributed to larger effective population sizes of the parasite lineages, the vagility and social behaviour of Rhabdomys, and the lack of host‐specificity observed in areas of host sympatry. Further, the patterns of genetic divergence within parasite and host lineages may also be largely attributed to historical biogeographic changes (expansion‐contraction cycles). It is thus evident that the association between P. arvicanthis and Rhabdomys has been shaped by the synergistic effects of parasite traits, host‐related factors and biogeography over evolutionary time.     

Chemotaxonomic Considerations of the n‐Alkane Composition in Pinus heldreichii,P. nigra,and P. peuce

The n‐alkane composition in the leaf cuticular waxes of natural populations of Bosnian pine (Pinus heldreichii), Austrian pine (P. nigra), and Macedonian pine (P. peuce) was compared for the first time. The range of n‐alkanes was wider in P. nigra (C₁₆ – C₃₃) than in P. heldreichii and P. peuce (C₁₈ – C₃₃). Species also diverged in abundance and range of dominant n‐alkanes (P. heldreichii: C₂₃, C₂₇, and C₂₅; P. nigra: C₂₅, C₂₇, C₂₉, and C₂₃; P. peuce: C₂₉, C₂₅, C₂₇, and C₂₃). Multivariate statistical analyses (PCA, DA, and CA) generally pointed out separation of populations of P. nigra from populations of P. heldreichii and P. peuce (which were, to a greater or lesser extent, separated too). However, position of these species on the basis of n‐alkane composition was in accordance neither with infrageneric classification nor with recent molecular and terpene investigations.     

Evaluation of attractants and traps for monitoring small banded pine weevil Pissodes castaneus

This study aimed to develop a semiochemical‐baited trapping system to monitor the populations of small banded pine weevil, Pissodes castaneus, a serious pest in Pinus sylvestris young stands that are weakened by biotic and abiotic factors. The scope of the work included the development of a dispenser for compounds (ethanol and α‐pinene) emitted by P. sylvestris and the pheromones of P. castaneus: grandisol and grandisal. Additionally, the effectiveness of beetle catches in different types of traps (unitrap, cross‐unitrap and long and short pipe traps) baited with a dispenser was assessed. The olfactometric studies showed that most of the newly hatched beetles that had not fed were attracted by a mixture of grandisol and grandisal. However, in the group of feeding beetles, half were attracted by a mixture of ethanol and α‐pinene. These results indicated that both pheromones and α‐pinene plus ethanol should be useful for capturing P. castaneus beetles. In the field trials, the highest efficiency was found in baited unitraps that caught up to several hundred P. castaneus beetles, while the baited cross‐unitraps caught up to a few dozen beetles. No insects were found in either type of baited pipe trap or in any of the unbaited control traps. The baited unitraps and cross‐unitraps also collected, with varied intensity, Hylobius abietis beetles, a serious pest of reforestations. These results indicate the possibility of using a unitrap baited with a 4‐component attractant for monitoring P. castaneus in integrated pest management for the protection of young forests.     

Contemporary evolution of a Lepidopteran species,Heliothis virescens,in response to modern agricultural practices

Adaptation to human‐induced environmental change has the potential to profoundly influence the genomic architecture of affected species. This is particularly true in agricultural ecosystems, where anthropogenic selection pressure is strong. Heliothis virescens primarily feeds on cotton in its larval stages, and US populations have been declining since the widespread planting of transgenic cotton, which endogenously expresses proteins derived from Bacillus thuringiensis (Bt). No physiological adaptation to Bt toxin has been found in the field, so adaptation in this altered environment could involve (i) shifts in host plant selection mechanisms to avoid cotton, (ii) changes in detoxification mechanisms required for cotton‐feeding vs. feeding on other hosts or (iii) loss of resistance to previously used management practices including insecticides. Here, we begin to address whether such changes occurred in H. virescens populations between 1997 and 2012, as Bt‐cotton cultivation spread through the agricultural landscape. For our study, we produced an H. virescens genome assembly and used this in concert with a ddRAD‐seq‐enabled genome scan to identify loci with significant allele frequency changes over the 15‐year period. Genetic changes at a previously described H. virescens insecticide target of selection were detectable in our genome scan and increased our confidence in this methodology. Additional loci were also detected as being under selection, and we quantified the selection strength required to elicit observed allele frequency changes at each locus. Potential contributions of genes near loci under selection to adaptive phenotypes in the H. virescens cotton system are discussed.     

Diving Into The Water: Cues Related to the Decision‐Making by an Egg Parasitoid Attacking Underwater Hosts

Although adult parasitoids spend a majority of their lives above ground, females of several species must search for their host in the water or on the soil. Adult parasitoids above ground can use a variety of sensory cues to detect their hosts from a distance. However, their sensory cues can be impaired from volatile chemicals, and their visual stimuli can be decreased while submerging or burrowing in the water of soil during their search for their hosts. Searching underwater or underground would incur high foraging costs, that is, time and energy consumption and increase risk of drowning. Therefore, to reduce such costs and increase searching efficiency, the decision on where to start submerging or burrowing for attacking hosts is important for parasitoids. Furthermore, there are no studies that have examined the cues of submerging or burrowing parasitoids on their exploit for the decision to attack their hosts. We have examined the cues used by the egg parasitoid Tiphodytes gerriphagus attacking underwater hosts. We compared the searching behaviors of T. gerriphagus among four oviposition site conditions. The four sites investigated were oviposition site with both host adult chemical residues and presence of eggs, with only the presence of eggs, with only the host adult chemical residues, and without any cue. Our results indicated that T. gerriphagus more frequently contacted and submerged at oviposition sites with the adult residues rather than at oviposition sites without them. Nonetheless, the presence of underwater host eggs did not affect the host‐searching behavior. This suggests that T. gerriphagus decided to submerge at the oviposition site in response to the adult residues. Furthermore, our observation also suggested that T. gerriphagus has already detected that the adult residues might be volatile before contacting the oviposition site. Finally, we will discuss the exploitation patterns of host‐searching cue by parasitoids that need to submerge from the context of its reliability and detectability problems.     

The right response at the right time: Exploring helminth immune modulation in sticklebacks by experimental coinfection

Parasites are one of the strongest selective agents in nature. They select for hosts that evolve counter‐adaptive strategies to cope with infection. Helminth parasites are special because they can modulate their hosts’ immune responses. This phenomenon is important in epidemiological contexts, where coinfections may be affected. How different types of hosts and helminths interact with each other is insufficiently investigated. We used the three‐spined stickleback (Gasterosteus aculeatus) – Schistocephalus solidus model to study mechanisms and temporal components of helminth immune modulation. Sticklebacks from two contrasting populations with either high resistance (HR) or low resistance (LR) against S. solidus, were individually exposed to S. solidus strains with characteristically high growth (HG) or low growth (LG) in G. aculeatus. We determined the susceptibility to another parasite, the eye fluke Diplostomum pseudospathaceum, and the expression of 23 key immune genes at three time points after S. solidus infection. D. pseudospathaceum infection rates and the gene expression responses depended on host and S. solidus type and changed over time. Whereas the effect of S. solidus type was not significant after three weeks, T regulatory responses and complement components were upregulated at later time points if hosts were infected with HG S. solidus. HR hosts showed a well orchestrated immune response, which was absent in LR hosts. Our results emphasize the role of regulatory T cells and the timing of specific immune responses during helminth infections. This study elucidates the importance to consider different coevolutionary trajectories and ecologies when studying host‐parasite interactions.     

Introduction history overrides social factors in explaining genetic structure of females in Mediterranean mouflon

Fine‐scale spatial genetic structure of populations results from social and spatial behaviors of individuals such as sex‐biased dispersal and philopatry. However, the demographic history of a given population can override such socio‐spatial factors in shaping genetic variability when bottlenecks or founder events occurred in the population. Here, we investigated whether socio‐spatial organization determines the fine‐scale genetic structure for both sexes in a Mediterranean mouflon (Ovis gmelini musimon × Ovis sp.) population in southern France 60 years after its introduction. Based on multilocus genotypes at 16 loci of microsatellite DNA (n = 230 individuals), we identified three genetic groups for females and two for males, and concurrently defined the same number of socio‐spatial units using both GPS‐collared individuals (n = 121) and visual resightings of marked individuals (n = 378). The socio‐spatial and genetic structures did not match, indicating that the former was not the main driver of the latter for both sexes. Beyond this structural mismatch, we found significant, yet low, genetic differentiation among female socio‐spatial groups, and no genetic differentiation in males, with this suggesting female philopatry and male‐biased gene flow, respectively. Despite spatial disconnection, females from the north of the study area were genetically closer to females from the south, as indicated by the spatial analysis of the genetic variability, and this pattern was in accordance with the common genetic origin of their founders. To conclude, more than 14 generations later, genetic signatures of first introduction are not only still detectable among females, but they also represent the main factor shaping their present‐time genetic structure.     

Cryptolaemus montrouzieri as a predator of the striped mealybug,Ferrisia virgata,reared on two hosts

The striped mealybug, Ferrisia virgata (Cockerell) (Hemiptera: Pseudococcidae), is a cosmopolitan pest of a variety of agricultural crops including cotton. To investigate the biological control potential of the predatory ladybird Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) against this pest, we evaluated its developmental and reproductive fitness when feeding on F. virgata reared on pumpkin fruits or on cotton leaves and compared this to a diet of Planococcus citri Risso (Hemiptera: Pseudococcidae) reared on pumpkin fruits. F. virgata and P. citri reared on pumpkins were equally suitable prey for the pre‐imaginal stages of C. montrouzieri. Duration of total immature development was 1 day longer in C. montrouzieri offered F. virgata reared on cotton as compared with F. virgata or P. citri reared on pumpkin, whereas no significant difference was observed in survival rates. Diet significantly influenced the reproductive fitness of C. montrouzieri. Females offered P. citri reared on pumpkin had significantly shorter pre‐oviposition periods and higher fecundity and fertility than those given F. virgata reared on pumpkin or cotton leaves. F. virgata grown on cotton leaves supported the reproduction of C. montrouzieri better than F. virgata reared on pumpkin. Our study established that C. montrouzieri can successfully complete its development and reproduction when fed exclusively on F. virgata and indicates its potential as a biological control agent of this emerging cotton pest.     

Applicability of AFLP Fingerprinting Markers to Molecular Discrimination of the Three Main Fungal Species Associated with Grapevine Decline in Spain

Diplodia seriata, Phaeomoniella chlamydospora and Phaeoacremonium aleophilum are the three main species associated with grapevine decline in Spain. AFLP markers were developed to discriminate Spanish populations of these species. The markers were used to genotype isolates of D. seriata, P. chlamydospora and P. aleophilum. AFLP markers were valuable in performing population genetic studies as genetic variability (K_x) ranged from 0.07 in the P. chlamydospora population to 0.28 in the D. seriata population. Species‐specific markers obtained using only two AFLP combinations clearly discriminate D. seriata, P. chlamydospora and P. aleophilum and are a useful tool in simultaneous identification tests.     

Development of the gregarious ectoparasitoid Nasonia vitripennis using five species of necrophagous flies as hosts and at various developmental temperatures

The utility of five species of necrophagous flies (Diptera) as pupal hosts for Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae) was examined by comparing incidences of parasitism, fecundity, and several features of wasp development at three rearing temperatures. Species differences in host suitability were evident in all life history features examined, with the highest incidences of parasitism, largest clutches and adult body sizes, and shortest periods of development occurring when the sarcophagid Sarcophaga bullata Parker served as hosts, regardless of temperature in which the wasps developed. Puparia of the calliphorids Lucilia illustris Meigen, Phormia regina Meigen, and Protophormia terraenovae Robineau‐Desvoidy were also accepted as hosts by the female parasitoids, albeit not equally so, and each yielded large, female‐biased broods. By contrast, pupae of the calliphorid Chrysomya rufifacies (Macquart) were not well suited to serve as an oviposition site or support the development of N. vitripennis. When successful parasitism did occur on any host species, duration of parasitoid development increased, adult body sizes were truncated, male‐biased sex ratios were produced, and mortality from egg hatch to adult emergence elevated with increasing rearing temperature. Unlike with the four other fly species, C. rufifacies did not yield any adult parasitoids when the rearing temperature was 35 °C. The results argue that developmental data determined for this wasp derived from a single host species is not sufficient for applying to all scenarios in which wasp development is necessary to estimate a postmortem interval or periods of insect activity.