Trapping of European buprestid beetles in oak forests using visual and olfactory cues

Trapping approaches developed for the emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), were adapted for trapping several European oak buprestid species. These approaches included the use of natural leaf surfaces as well as green and purple plastic in sticky trap designs. Plastic surfaces were incorporated into novel ‘branch‐trap’ designs that each presented two 5 × 9‐cm² rectangular surfaces on a cardboard structure wrapped around the leaves of a branch. We used visual adult Agrilus decoys in an attempt to evoke male mating approaches toward the traps. Our first experiment compared the attractiveness of visual characteristics of the surfaces of branch‐traps. The second looked at the effect on trap captures of adding semiochemical lures, including manuka oil, (Z)‐3‐hexen‐1‐ol, and (Z)‐9‐tricosene. In total, 1 962 buprestid specimens including 14 species from the genus Agrilus were caught on 178 traps in a 22‐day time‐span. Overall, the green plastic‐covered branch‐traps significantly out‐performed the other trap designs. We further found that the presence of an EAB visual decoy placed on the trap surface often increased captures on these green traps, but this effect was stronger for certain Agrilus species than for others. The visual decoy was particularly important for the most serious pest detected, Agrilus biguttatus Fabricius, which was captured 13 times on traps with decoys, but only once without a decoy. There were some small but significant effects of odor treatment on the capture of buprestids of two common species, Agrilus angustulus Illiger and Agrilus sulcicollis Lacordaire. There were also 141 Elateridae specimens on these traps, which were not influenced by trap type or decoys. The results suggest that small branch‐traps of this nature can provide a useful new tool for monitoring of buprestids, which have the potential to be further optimized with respect to visual and olfactory cues.     

Determination of the Luciferin Contents in Luminous and Non-Luminous Beetles

The contents of firefly luciferin in luminous and non-luminous beetles were determined by the methods of HPLC with fluorescence detection and the luminescence reaction of luciferin and firefly luciferase. Luminous cantharoids and elaterids contained various amounts of luciferin in the range of pmol to hundreds of nmol, but no luciferin was detected in the non-luminous cantharoids and elaterids.     

Anther cap retention prevents self-pollination by elaterid beetles in the South African orchid Eulophia foliosa

BACKGROUND AND AIMS: Pollination by insects that spend long periods visiting many flowers on a plant may impose a higher risk of facilitated self-pollination. Orchids and asclepiads are particularly at risk as their pollen is packaged as pollinia and so can be deposited on self-stigmas en masse. Many orchids and asclepiads have adaptations to limit self-deposition of pollinia, including gradual reconfiguration of pollinaria following removal. Here an unusual mechanism--anther cap retention--that appears to prevent self-pollination in the South African orchid Eulophia foliosa is examined. METHODS: Visits to inflorescences in the field were observed and pollinators collected. Visitation rates to transplanted inflorescences were compared between a site where putative pollinators were abundant and a site where they were rare. Anther cap retention times were determined for removed pollinaria and atmospheric vapour pressure deficit was recorded concurrently. Anther cap anatomy was examined using light microscopy. KEY RESULTS: Eulophia foliosa is pollinated almost exclusively by Cardiophorus obliquemaculatus (Elateridae) beetles, which remain on the deceptive inflorescences for on average 301 s (n = 18). The anther cap that covers the pollinarium is retained for an average of 512 s (n = 24) after pollinarium removal by beetles. In all populations measured, anther cap dimensions are greater than those of the stigmatic cavity, thus precluding the deposition of self-pollinia until after the anther cap has dropped. An anatomical investigation of this mechanism suggests that differential water loss from regions of the anther cap results in opening of the anther cap flaps. This is supported by observations that as atmospheric vapour pressure deficits increased, the duration of anther cap retention was reduced. CONCLUSIONS: Flowers of E. foliosa are specialized for pollination by elaterid beetles. Retention of anther caps for a period exceeding average visit times by beetles to inflorescences appears to prevent facilitated self-pollination in E. foliosa effectively.     

Contribution to the knowledge of the click beetle genus Zorochros (Coleoptera: Elateridae) from Saudi Arabia

Examination of specimens of Elateridae revealed new generic and species records for Saudi Arabia. Zorochros amalec (Peyerimhoff) is recorded from Al Majardah, and Zorochros yosrae sp. n. is described as a new species from Thalouth Almanazar.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:E4B9EB99-BE55-4884-B220-BF9928926312     

Differential responses of three Agriotes click beetle species to pheromone traps

1 Previous work had suggested that adult male click beetles (Agriotes spp.) show differential responses to species specific pheromone traps. This hypothesis was tested using mark–release–recapture methods to estimate the maximum sampling range and the effective sampling area of traps for three species. 2 Captured beetles of the species Agriotes lineatus, Agriotes obscurus and Agriotes sputator were marked to show the direction of release, the distance of the release point from the trap and the replicate. Analysis of variance showed that there were significant differences in recapture rates between species and release distances. There were no significant differences between release direction and replicates. 3 Calculated linear speeds suggested differences in movement rates in the order: A. lineatus > A. obscurus > A. sputator. There were also substantial differences between the species in the maximum sampling ranges and effective sampling areas of the traps. These placed the species in the same order. 4 The results are used to estimate the minimum cost of mass trapping programmes to prevent males from mating, giving values of €165/ha/year (A. lineatus), €247.5/ha/year (A. obscurus) and €2343/ha/year (A. sputator). 5 Implications for the use of pheromone traps in wireworm pest management are discussed. It is concluded that current U.K. recommendations based on the cumulative total catch of the three species over a sampling season can be improved by considering the spatial relationships between the adult trapping system and larval distribution. The current constraint to this is the general inability to separate wireworms into species.     

Influence of harvest gaps and coarse woody material on click beetles (Coleoptera: Elateridae) in Maine’s Acadian forest

In order to maintain biodiversity in forests, it has been recommended that harvests be designed after patterns of natural disturbance. Using a long-term study that includes harvest treatments designed to emulate tree-fall gap disturbances in Maine’s Acadian forest, we examined how the species richness, abundance, diversity, and assemblage similarity of click beetles inhabiting coarse woody material (CWM) were affected by gap harvesting and CWM characteristics (diameter, degree of decay, and type of wood). There were few differences in beetle assemblages between 0.07 and 0.12 ha harvest gap treatments. Four of the most common species had higher abundances under a closed forest canopy than within harvest gaps. Species richness and total abundance were higher in CWM that had larger diameters and were more decayed. Species assemblages also differed with the degree of wood decomposition. Diversity was higher in CWM from softwood trees than hardwood trees. Results from this study suggest that small (<0.2 ha) harvest gaps with living trees retained throughout the gap can maintain click beetle assemblages similar to that of an unharvested forest. Forest managers also need to address the temporal continuity of CWM, including different types of wood (hardwood and softwood), a range of decay conditions, and a range of diameter classes, especially larger diameters (>35 cm).     

Morbidity and recovery of the Pacific Coast wireworm, Limonius canus, following contact with tefluthrin-treated wheat seeds

Late instars of the Pacific Coast wireworm, Limonius canus (LeConte) (Coleoptera: Elateridae), were exposed to wheat seeds treated with tefluthrin at 5, 10, 15, 20, or 30 g active ingredient (a.i.) per 100 kg wheat seed for 1, 2, 4, 8, or 16 min. All wireworms were moribund within 20 min of first exposure and recovered fully within 12 h. The time required for recovery (t_r) after a single exposure increased with duration of exposure (e) and concentration (c), but decreased with wireworm weight (w), expressed as (t_r)^0.5 = 5.2812 + 0.9407e – 0.0259e² + 0.1569c + 0.0254ec – 0.0174w – 0.0057ew. For wireworms exposed to treated seeds for 2 min, the time required for induction of morbidity decreased as concentration of tefluthrin increased and as wireworm weight decreased, expressed as (t_i)^0.5 = 2.613 – 0.039c + 0.018w, where t_i is the induction time of morbidity, and c and w are as above. Wireworms re‐exposed to tefluthrin‐treated seeds after recovery from previous exposure were again moribund within 20 min of exposure, but recovery was significantly more rapid if the second exposure was 2, 4, 6, 8, 12, 18, 24, and 48 h after recovery from first exposure. Recovery from a second exposure was not significantly faster when the second exposure was 96 h after recovery from the first exposure. The ability of wireworms to recover from tefluthrin‐induced morbidity may seriously limit the efficacy of this insecticide in actually reducing wireworm populations in the field.     

Assessment of the range of attraction of pheromone traps to Agriotes lineatus and Agriotes obscurus

• 1 The range of attraction of YATLOR pheromone traps was studied to gain information on the number of traps needed for mass trapping of males of two Agriotes species.
• 2 Male click beetles of the species Agriotes lineatus (L.) and Agriotes obscurus (L.) (25–30 individuals per release point) were marked and released at a distance of 2, 5, 10, 15, 20 and 60 m from a pheromone trap both along and opposite to the known prevailing wind direction. Traps were regularly inspected over approximately 1 month. The percentage of recaptured beetles was calculated and analyzed using analysis of variance. Maximum sampling ranges and effective sampling areas were calculated.
• 3 Averaged over all five trials and distances, approximately 40% of the released beetles (A. lineatus and A. obscurus) were recaptured. The percentage recapture of male adults was significantly affected by release distance, whereas no differences were found for species and release direction.
• 4 Males were recaptured from all release points and the percentage recapture decreased (in part significantly) with increasing distance from 76% (2 m) to 35% (15 m) and 9% (60 m), respectively. Most of the beetles were recaptured within the first 3 days after release, independent of the distance, except 60 m. The effective sampling area for A. lineatus was 1089 m² after 12 days and increased to 1735 m² after 30 days. Corresponding values for A. obscurus were considerably higher: 1518 m² for 12 days and 2633 m² for 30 days.
• 5 We conclude that the range of attraction of the pheromone traps for A. lineatus and A. obscurus is comparatively low, providing high percentage recapture only for release distances up to 10 m. Accordingly, any approach targeted on preventing mating by male mass trapping would require a dense network of pheromone traps.

     

On taxonomy and distribution of fossil Cerophytidae (Coleoptera: Elateriformia) with description of a new Mesozoic species of Necromera Martynov 1926

In this paper the data on fossils of the family Cerophytidae are reviewed. New synonymy on generic names Necromera Martynov 1926 (proposed in composition of the family Oedemeridae); Idiomerus Dolin in Dolin et al. 1980, n. syn. (proposed in composition of Elateridae) and Leptocnemus Hong & Wang 1990, n. syn. (proposed without any family attribution) is established. New materials on this family from Mesozoic deposits of Asia are cited. As a result, it was established that this spreads in deposits of both Upper Jurassic and Lower Cretaceous. Mercata festira Lin 1986 described from Lower Jurassic as member of Silphidae and Abrotus reconditus Dolin in Dolin et al. 1980 described from Upper Jurassic as a member of Elateridae are transferred to Cerophytidae. Diagnoses of the genus Necromera and family Cerophytidae in compression fossils are elaborated. Necromera admiranda n. sp. is described from the Upper Jurassic-Lower Cretaceous in Liaoning, China. The historical development of the family from the Lower Jurassic is discussed.