First field evidence that parasitoids use upwind anemotaxis for host-habitat location

The direction of flight of natural populations of Phradis interstitialis (Thomson), Tersilochus obscurator Aubert (both Hymenoptera: Ichneumonidae), and Platygaster subuliformis (Kieffer) (Hymenoptera: Platygastridae), parasitoids of three crucifer‐specialist herbivores, to and from their hosts’ host plant [oilseed rape, Brassica napus L. (Brassicaceae)] was studied in the field within a heterogeneous arable environment. Double‐sided Malaise traps encircling a plot of winter oilseed rape (cultivar Lutin) were used to sample the parasitoids as they flew towards and away from the plot during spring and summer. Daily trap catch of parasitoids and trap air flow were compared using Spearman's rank correlation. For all 14 insect days analysed, and for each species, the correlations between daily catch of parasitoids into distal halves of traps (relative to the plot) and wind direction were negative, significantly so on half the days analysed. This confirmed that flights towards the plot were by upwind anemotaxis. In contrast, the correlations between daily catch of parasitoids into proximal halves of traps (relative to the plot) and wind direction were most often crosswind; they were never strongly nor significantly either negative or positive. Implications of the results for integrated pest management strategies incorporating biological control with these parasitoids are discussed.     

Rainfall and parasitic wasp (Hymenoptera: Ichneumonoidea) activity in successional forest stages at Barro Colorado Nature Monument, Panama, and La Selva Biological Station, Costa Rica

1 In 1997, we ran two Malaise insect traps in each of four stands of wet forest in Costa Rica (two old‐growth and two 20‐year‐old stands) and four stands of moist forest in Panama (old‐growth, 20, 40 and 120‐year‐old stands). 2 Wet forest traps caught 2.32 times as many ichneumonoids as moist forest traps. The average catch per old‐growth trap was 1.89 times greater than the average catch per second‐growth trap. 3 Parasitoids of lepidopteran larvae were caught in higher proportions in the wet forest, while pupal parasitoids were relatively more active in the moist forest. 4 We hypothesize that moisture availability is of key importance in determining parasitoid activity, community composition and trophic interactions.     

Effect of diflubenzuron on flight of adult aquatic insects (Plecoptera, Trichoptera) following emergence during the second year after aerial application

With Malaise traps, we monitored the flight of adult Plecoptera and Trichoptera following emergence from headwater streams in the Fernow Experimental Forest, WV, during the second year after application of diflubenzuron. We placed five traps at various distances from each stream during May through September of 1991, 1992, and 1993. We collected pretreatment samples during the first year. In May 1992, diflubenzuron was applied to two watersheds, and the other two watersheds were used as untreated references. The 1992 study tested the effects of diflubenzuron that fell directly into the streams or were washed into the stream during the first year. For 1993, we tested the hypothesis that diflubenzuron affected adult flight following emergence during the year following abscission and possible ingestion of the treated leaves. The analysis compared the regressions of the number of adults caught in each trap versus distance of the trap from the stream among years and between treatments for each species. The flight of the stonefly Leuctra ferruginea (Walker) was reduced in the treatment watersheds compared with the reference watersheds during the year following abscission of the treated leaves. Adult flight of other species did not decrease in the treatment watersheds during 1993. These results show a relatively small effect of diflubenzuron on these aquatic insects; however, our study involved only a single application of diflubenzuron. Additional research may be needed to predict the possible effects of multiple applications of diflubenzuron over several years as often occurs during actual efforts to suppress gypsy moth, Lymantria dispar (L.).     

Reproductive phenologies in a diverse temperate ant fauna

Abstract.  1. Ant nuptial flights are central to understanding ant life history and ecology but have been little studied. This study examined the timing of nuptial flights, the synchronicity of nuptial flights (as a potential index of mating strategy), and variation in nuptial flights with elevation and among years in a diverse temperate ant fauna.
2. Flights occurred throughout the year, but were concentrated in the beginning of summer and in early fall (autumn). Relative to the entire flight season, closely related species tended to be more likely than expected by chance to fly at similar times, perhaps because of phylogenetic constraints on life history evolution.
3. Flights were relatively synchronous within species for nearly all species considered, but synchronicity did not appear to be a robust estimate of overall mating strategy.
4. Overall patterns in nuptial flights among species and the timing of flights for individual species varied with elevation, but did not vary greatly among years.
5. Although this study is one of the most comprehensive on the reproductive flight phenologies of ants, much remains to be learned about the causes and consequences of such spatial and temporal variation in flight phenology.     

Efficiency of Malaise traps and colored pan traps for collecting flower visiting insects from three forested ecosystems

Pan and Malaise traps have been used widely to sample insect abundance and diversity, but no studies have compared their performance for sampling pollinators in forested ecosystems. Malaise trap design and color of pan traps are important parameters that influence insect pollinator catches. We compared pan trap (blue, yellow, white, and red) and Malaise trap catches from forests in three physiographic provinces (Piedmont, Coastal Plain, and Blue Ridge) of the southeastern United States. Similarities in trap performance between sites were observed with blue pan traps being most effective overall. Our results showed that various pollinator groups preferred certain pan trap colors and that adding color to Malaise traps influenced insect pollinator catches. However, pan traps generally caught more pollinators than Malaise traps. Because of their low cost and simplicity, using several colors of pan traps is an effective way to sample relative abundance and species richness of flower-visiting insects.     

Individual and sex‐related patterns of prolonged flights during both day and night by great reed warblers crossing the Mediterranean Sea and Sahara Desert

A wide variety of the barrier crossing strategies exist among migrating songbirds, ranging from strict nocturnal flights to non‐stop flights over a few days. We evaluate barrier crossing strategies in a nocturnally migrating songbird crossing the Mediterranean Sea and the Sahara Desert, the great reed warbler, exploring variation between the sexes and within individuals. We used data from 31 year‐round light‐level geolocators tracks from 26 individuals (13 males and 13 females), with four individuals tracked for 2–3.5 consecutive years. Almost all individuals (25 of 26) prolonged their flights into the day at least on one occasion. The mean duration of these prolonged flights was 19.9 h and did not differ between sexes or seasons. Fifteen birds performed non‐stop flights during more than one full day and night (≥ 24 h; mean = 31.9 h; max = 55 h) in autumn and/or spring, but these flights were generally too short to cross an entire barrier (such as the Sahara Desert) in one non‐stop flight. Patterns of prolonged flights showed considerable within‐individual variation in females between seasons (autumn versus spring) and in both males and females between years, suggesting high individual flexibility in migration strategy. Significantly more males than females performed prolonged flights during autumn migration, but not spring, possibly reflecting sex‐specific carry‐over effects. We conclude that great reed warblers have the ability to conduct prolonged continuous flights for up to several nights and days, which potentially would allow them to cross the Sahara Desert in one non‐stop flight. However, they typically use a mixed strategy of several nocturnal flights with intermittent stopovers in combination with 1–3 prolonged flights. Prolonged flights covered less than half (44%) of the total flight time across the barriers, and the diurnal parts of the flights covered only 18% of this time.     

Migration to and dispersal from oilseed rape by the pollen beetle,Meligethes aeneus,in relation to wind direction

1 Host‐plant‐odour‐induced upwind anemotaxis is accepted as the main mechanism by which herbivorous insects find their host plant within an heterogenous environment, but field data supporting this hypothesis are scarce. 2 The flight directions of the pollen beetle Meligethes aeneus to and from a plot of winter oilseed rape and the direction of the wind were recorded concurrently. The beetles were sampled by eight double‐sided window traps encircling the plot. Distal sides of the traps, relative to the plot, sampled the beetles as they flew towards the plot, whereas the proximal sides of the traps sampled them as they flew away from the plot. Paired data on daily catch of beetles in distal or proximal traps and the volume of air impacting each trap were compared. 3 Correlations between daily catch of M. aeneus into distal traps and trap wind volume were negative, indicating that flights by both overwintered‐ and new‐generation insects towards the plot were upwind. 4 Correlations between daily catch of M. aeneus into proximal traps and trap wind volume varied with generation. Catch of overwintered‐generation M. aeneus was negatively correlated with trap wind volume, indicating that flight was upwind. Proximal trap catch of the new‐generation M. aeneus was weakly/modestly positively correlated with trap wind volume, indicating that flights were downwind or crosswind. 5 Understanding the effect of wind direction on flight of M. aeneus holds potential for improving the forecasting of their arrival and spatial distribution on the crop for integrated pest management.     

Seasonal flight activity of sawflies (Hymenoptera, Symphyta) in submontane region of the Western Carpathians, Central Slovakia

Species representation and seasonality of adult sawflies (Symphyta) were studied using Malaise traps at three submontane study sites (Hriňová — HR, Mošovce — MO and Štefanová — ŠT) in the Western Carpathians (Central Slovakia). One trap was operated at each study site continuously during the growing season, in MO in 1992, in HR in 1995 and in ŠT in 1996. A total of 9,281 adults representing 244 species in 9 families were collected. Very rich sawfly assemblages were found. The highest species richness was in MO (181 species), followed by ŠT (153 species) and HR (118 species). Pseudodineura fuscula was recorded from Slovakia for the first time. Adults were present in traps from the end of April through the first half of October. Most species occurred from the second half of May through the first half of June and finished flight activity by the end of June. Seasonal flight activities of the 16 most abundant species are analysed and discussed.     

Fighting and mating behaviors of dimorphic males in the ant

Colony composition inCardiocondyla wroughtoni and the fighting and mating behaviors of 2 types of males, alates and ergatoids, are described. This species is polygynous, with a mean of 7.0 queens per nest, and forms polycalic colonies. Within nests, ergatoid males fight with each other, leading to the death of all but one in single nests. On the other hand, alate males exhibit no aggressive behavior towards any of their colony members. Both types of males conduct intranidal mating with their sisters, though the alate males also conduct nuptial flights. Many alate females leave their maternal nest even if they have already been inseminated by intranidal mating.     

黑龙江省哈尔滨地区吸虫塔有翅蚜种群动态

【目的】明确吸虫塔对作物蚜虫防控的指导意义,明确中国黑龙江省哈尔滨地区有翅蚜(和大豆蚜)的种群动态,为大豆蚜虫防控提供预警信息。【方法】2009至2012年通过吸虫塔监测哈尔滨地区有翅蚜及有翅大豆蚜动态结合当年田间大豆蚜动态调查。【结果】哈尔滨吸虫塔全年收集有翅蚜量为0.6~1.7万头不等。具1~3个高峰(不同年份有翅蚜发生高峰数量不同),高峰期时间1个月左右,位于7月中旬至10月中旬之间。周有翅蚜量达200头时预示着有翅蚜高峰期的到来,高峰期有翅蚜量可占年有翅蚜量的90%以上。同一地区不同年份有翅蚜高峰期时间不同。吸虫塔有翅大豆蚜亦具1~3个高峰期,时间位于当年有翅蚜的高峰期时间内,为短短的1周或几周,高峰期蚜量占全年采集有翅大豆蚜量的80%~95%。田间大豆蚜只存在一个高峰,2009、2010、2012年田间大豆蚜高峰期均与吸虫塔收集的大豆蚜高峰期相重叠,且峰值日期一致。【结论】吸虫塔可以很好地反应当年田间大豆蚜的种群动态,表现在高峰期及高峰点的预测,可为大豆蚜的预测预报提供预警信息。     

A new window trap used in the assessment of the flight periods of Chironomidae and Simuliidae (Diptera)

SUMMARY. 1. A window trap is described which has been found useful in the study of the fight periodicity of chironomids and simuliids. the trap is simple to construct and can be operated in high winds.
2. Window traps were operated in 1977 and 1478 at Lake Myvatn. Iceland, when thirty-nine chironomid species and two simuliid species were caught. Most of the chironomids had two peaks in flight activity per year. e.g. Eukiefferietla minor, Cricotftpus tibialis. Pogonocladius consohrinus, Tanytaraus gracilentus and Micropsectra airofasciata. Chironomus islandicus and Heterotrissocladius grimshawi had one peak in activity in all traps. The flight activity of Prodadius istandicus, Orthocladius oblidens and Micropsectra Undrothi varied greatly between traps and years. Simulium vittatum had two peaks in flight activity, corresponding to the two generations developing per year. Variation in trap catches of .S. vittatum reflected populalion changes measured independently in a study of larval population dynamic     

Flight activity of adult stoneflies in relation to weather

Abstract. 1. Dispersal of adult aquatic insects between streams may have important consequences for local and regional population dynamics, but little is known about how dispersal is affected by weather conditions.
2. The influence of meteorological variables on flight activity of adult stoneflies (Plecoptera: Leuctridae, Nemouridae, and Chloroperlidae) was investigated using Malaise traps adjacent to three upland streams in the Plynlimon area of mid Wales, U.K.
3. Numbers of adult stoneflies captured weekly in the traps were related positively to air temperature and related negatively to wind speed. Meteorological conditions during daylight showed stronger relationships with flight activity than did conditions at night.
4. There was inter-site variation in the strength of weather effects on stonefly flight. Wind speed was significant at only one site, which had higher average wind speed than the other sites.
5. Annual variation in weather conditions during adult flight periods may result in varying extent of dispersal between sites, influencing community dynamics over a wide area.     

Dispersal patterns of oribatid mites across habitats and seasons

Oribatid mites are tiny arthropods that are common in all soils of the world; however, they also occur in microhabitats above the soil such as lichens, mosses, on the bark of trees and in suspended soils. For understanding oribatid mite community structure, it is important to know whether they are dispersal limited. The aim of this study was to investigate the importance of oribatid mite dispersal using Malaise traps to exclude sole passive wind-dispersal. Oribatid mite communities were collected over a 3-year period from five habitat types (coniferous forests, deciduous forests, mixed forests, meadows, bog/heathlands sites) and three seasons (spring, summer, autumn) in Sweden. Mites entered traps either by walking or by phoresy, i.e., by being attached to flying insects. We hypothesized (1) that oribatid mite communities in the traps differ between habitats, indicating habitat-limited dispersal, and (2) that oribatid mite communities differ among seasons suggesting that dispersal varies due to changing environmental conditions such as moisture or resource availability. The majority of the collected species were not typically soil-living species but rather from habitats such as trees, lichens and mosses (e.g., Carabodes labyrinthicus, Cymbaeremaeus cymba, Diapterobates humeralis and Phauloppia lucorum) indicating that walking into the traps or entering them via phoresy are of greater importance for aboveground than for soil-living species. Overall, oribatid mite communities collected in the traps likely originated from the surrounding local habitat suggesting that long distance dispersal of oribatid mites is scarce. Significant differences among seasons indicate higher dispersal during warm and dry periods of the year. Notably, 16 species of oribatid mites collected in our study were sampled for the first time in Sweden. This study also demonstrates that Malaise traps are a meaningful tool to investigate spatial and temporal patterns of oribatid mite communities.

     

Influence of trap type, trap colour, and trapping location on the capture of the pine moth, Thaumetopoea pityocampa

Studies were conducted to evaluate the effect of type, location, and colour of traps baited with 1 mg of the sex pheromone (Z)‐13‐hexadecen‐11‐ynyl acetate in polyethylene vials on the capture of the pine processionary moth, Thaumetopoea pityocampa (Denis & Schiffermüller) (Lepidoptera: Thaumetopoeidae), males. The experiments were carried out during two flight seasons in 2002 and 2003 at a low elevation Mediterranean pine forest on the hill of Goritsa (Magnesia, Thessaly, Central Greece). The hill is covered by approximately 120 ha of pines, among which Pinus brutia Ten. (Pinaceae) is predominant with Pinus halepensis Mill. (Pinaceae) as second most common species. Among the commercially available trap types used, the Delta and Pherocon II captured significantly more males than the Funnel trap. Furthermore, pine density had a significant effect on trap type and trap colour catches. Delta traps caught significantly more adults than the other two trap types in the low density pine stand, while in the medium and high‐density pine stands no significant differences were noted between Delta and Pherocon II traps. In addition, trap colour performance varied according to pine density; white‐ and yellow‐coloured traps caught significantly more males than the other two trap colours in the high‐density stand. The first adults were captured in traps during May, and traps continued to capture adults in low numbers (< two individuals per trap) until mid‐June. A period of 3–4 weeks of no trap captures followed until mid‐July, when captures restarted, at low numbers. The peak of T. pityocampa flight was observed during late August–September.     

Beetle assemblages from an Australian tropical rainforest show that the canopy and the ground strata contribute equally to biodiversity

There remains great uncertainty about how much tropical forest canopies contribute to global species richness estimates and the relative specialization of insect species to vertical zones. To investigate these issues, we conducted a four-year sampling program in lowland tropical rainforest in North Queensland, Australia. Beetles were sampled using a trap that combines Malaise and flight interception trap (FIT) functions. Pairs of this trap, one on the ground and a second suspended 15-20 m above in the canopy were located at five sites, spaced 50 m or more apart. These traps produced 29986 beetles of 1473 species and 77 families. There were similar numbers of individuals (canopy 14473; ground 15513) and species (canopy 1158; ground 895) in each stratum, but significantly more rare species in the canopy (canopy 509; ground 283). Seventy two percent of the species (excluding rare species) were found in both strata. Using IndVal, we found 24 and 27% of the abundant species (n>or=20 individuals) to be specialized to the canopy and the ground strata, respectively, and equivalent analyses at the family level showed figures of 30 and 22%, respectively. These results show that the canopy and the ground strata both provide important contributions to rainforest biodiversity.     

Can Malaise traps be used to sample spiders for biodiversity assessment?

Malaise traps are typically used to sample a range of flying insect groups; however non-target taxa such as spiders may also be collected in large numbers. In this study, spiders were sampled in peatlands and wet grasslands and catches in Malaise and pitfall traps were compared in order to determine the adequacy of Malaise traps for use in spider biodiversity assessment. Overall, the number of species and individuals caught in Malaise and pitfall traps were comparable, although more species were sampled in Malaise traps in locations with a greater structural diversity of the vegetation. The spider fauna sampled by the Malaise traps differed from that of the pitfall traps, but both methods consistently separated the species assemblages by biotope. These results demonstrate that Malaise traps are effective at sampling spiders and indicate that they can be used in biodiversity assessment. In addition the complementary species sampled by each method mean that employing both techniques will be useful where a full inventory of the species is required. The authors do not suggest that Malaise traps should be used solely to sample spiders; however, if traps are set to collect insects, identification of the spiders sampled may reduce the need to employ additional sampling techniques.     

THE COMPARISON OF YELLOW CYLINDRICAL, FLAT AND WATER TRAPS, AND OF JOHNSON SUCTION TRAPS, FOR SAMPLING APHIDS

Different traps were compared to find the type most suitable for studying aphid vectors of plant viruses quantitatively.
A Moericke water trap caught more aphids than a flat sticky trap of equal area. A flat sticky trap (930 sq. cm.) caught half as many aphids as a cylindrical trap (945 sq. cm.), which caught about one-third as many as a water trap (1200 sq. cm.) or a Johnson suction trap (9 in. fan) when operated at between 2 and 3 ft. over bare soil.
Yellow traps caught proportionally more Tuberculoides annulatus , and in summer more Capitophorus species than a suction trap, but significantly fewer Anoecia corni, Sitobium spp. and Pemphigus bursarius. Traps with a level surface caught proportionally more Brevicoryne brassicae, Aphis fabae and Myzus persicae , but fewer Anoecia corni and Drepanosiphum plantanoides than vertical cylindical traps. Attraction by colour influences the catch on horizontal traps more than on cylindrical traps because there is less impaction by the wind.
Only suction traps indicate the number of aphids per unit volume of air and are non-selective, but they are expensive and require an electric power supply. Water traps effectively catch those aphids that are attracted to yellow, but they require frequent attention. Sticky traps catch fewer aphids than either suction or water traps, but they can be left unattended for about 2 weeks. Flat sticky traps catch aphids likely to land on a crop, and cylindrical traps show when aphids are in the air, but not if those aphids are able or wanting to land. For routine work cylindrical sticky traps have other advantages; they are cheap and do not require skilled handling, and their catches of alate Myzus persicae have been correlated with the spread of some plant viruses.     

Cattle-tsetse contact in relation to the daily activity patterns of Glossina morsitans submorsitans in The Gambia

Abstract. The daily flight activity patterns of one of the main vectors of animal trypanosomiasis in West Africa, Glossina morsitans submorsitans , were assessed using four different methods. Results from all the methods showed that there was some flight activity nearly every hour in all seasons but they differed in the level of contact between grazing cattle herds and G.m.submorsitans. In the late dry season, trap data indicated that there was negligible activity from midday to late afternoon, whereas observations of tsetse contact with cattle herds or hand-net collections on herd followings showed no fall in attack rates on the cattle by G.m.submorsitans.
Differences between trap and animal-baited collection data may be attributable to the type of G.m.submorsitans sampled by each method. Male G.m.submorsitans captured by traps were more fat depleted than those caught on ox-baited flyrounds or by hand-net collections on herd followings. All methods showed that male G.m.submorsitans were most fat depleted in the late dry season and least in the early dry season. It was concluded that the traps were mainly sampling the spontaneous flights of G.m.submorsitans. Hunger and endogenous rhythms increase the likelihood of spontaneous flights towards dusk, particularly in conditions such as those at midday in the very hot, late dry season. However, the presence of cattle herds in infested habitats probably activated nearby G.m.submorsitans and the continual movement through the grazing areas ensured contact with tsetse throughout grazing.
The data indicated that strategic management of herd grazing times cannot eliminate the risk of trypanosomiasis transmission occurring, irrespective of the harshness of the dry season climate. An assessment of the level of this risk could only be measured suitably by collecting tsetse using animal-baited methods, not from trap data.     

An analysis of an adult Trichoptera community in the Laurentian highlands of Quebec

The adult Trichoptera communities of a small watershed in the Québec Laurentian Hills were studied during two years with emergence and light traps.
Some 180 species and more than 164500 specimens were collected, belonging mainly to the families Hydropsychidae, Polycentropodidae and Leptoceridae; the Limnephilidae with 41 species were the most diverse family.
A comparison of catches in emergence and light traps revealed the importance of species from distant or specialized habitats in the composition of local communities. Two series of light trap catches show little similarity (Sanders index) although the traps were only some 60 m apart; this is in accordance with the suspected limited range of efficiency of light traps.
The Shannon-Wiener diversity index, the Simpson dominance index as well as the Lloyd and Ghelardi equitability index have been used to describe community structure; our four data series have also been shown to conform to the log-normal frequency distribution of Preston.
The sex-ratios of the abundant species are given. In most light trap series and in half the emergence trap series, the ratio differs significantly from 50:50; there is however no overall dominance of one sex. Differences exist between the ratios obtained for the same species in the two types of traps and probably reflect sexual differences in behaviour at light.     

The Functions of Song in the Serin

The function of song in the serin Serinus serinus was investigated by measuring variation in singing time and song flights by the male, and nest building by the female during the prelaying and laying period, and by correlating nest building, extra-pair copulation attempts and chasing of the female with male singing time and song flights between pairs. Both singing time and nest building varied in relation to the female fertile period, peaking at day −4. Moreover, nest-building activity correlated with singing time, but not song flights, between pairs. This suggests that song may have a function in stimulating the female to nest build or begin rapid yolk deposition. Pair copulations were not correlated with singing time or song flights either over days relative to laying or between pairs and pairs were not more likely to copulate in a given minute of observation when the male had sung in the previous minute than when he had not. However, extra-pair copulation attempts and chasing of the female showed a tendency to be negatively correlated with song flight but not singing time, between pairs. This suggests that song flight may have a function in discouraging sexual competition from other males.