The first mainland European Mesozoic click-beetle (Coleoptera: Elateridae) revealed by X-ray micro-computed tomography scanning of an Upper Cretaceous amber from Hungary

Fossil bioinclusions in amber are invaluable source of information on the past evolution and diversity of various organisms, as well as on the paleoecosystems in general. The click-beetles, Elateridae, which originated and greatly diversified during the Mesozoic, are mostly known from the adpression-like fossils, and their diversity in the Cretaceous ambers is only poorly documented. In this study, we describe a new click-beetle based on an incomplete inclusion in ajkaite, an Upper Cretaceous (Santonian) amber from the Ajka Coal Formation from Hungary. We used X-ray micro-computed tomography scanning to reconstruct its morphology because it is deposited in an opaque piece of amber. Our results suggest that the newly described Ajkaelater merkli gen. et sp. nov. belongs to subfamily Elaterinae. It represents the first Mesozoic beetle reported from Hungary, and the first Mesozoic Elateridae formally described from mainland Europe. Our discovery supports an Eurasian distribution and diversification of Elaterinae already in the Cretaceous. The paleoenvironment of the Ajka Coal Formation agrees well with the presumed habitat preference of the new fossil taxon. The discovery of a presumably saproxylic click-beetle shed further light on the yet poorly known paleoecosystem of the Santonian present-day western Hungary.

The Effect of Simulated Seasonal Temperatures On Metarhizium Brunneum-Associated Mortality In Two Click Beetle Species, And A Degree-Day Infection Model

Wireworms (Coleoptera: Elateridae), the larvae of adult click beetles are subterranean and generalist crop pests that can be difficult to target. Targeting adult beetles, however, may be an effective method to lower wireworm populations. Metarhizium brunneum (Petch) kills click beetles but the mortality rate was expected to vary according to temperature. Using a thermal gradient plate to simulate daily oscillating temperatures for April, May, and June, the effectiveness of M. brunneum strains LRC112 and F52 in causing mortality to Agriotes obscurus (L.) and A. lineatus (L.) beetles was studied. Mortality was fastest in beetles exposed to June temperatures and slowest in those exposed to April temperatures, with differences among beetle species x M. brunneum strain combinations. Warmer temperatures resulted in more rapid mycelial outgrowth and conidiation in beetle cadavers, with only A. obscurus infected with M. brunneum LRC112 attaining near 100% conidiation. The number of degree days required to kill 50% of the beetles (LDD50) was least for A. obscurus infected with M. brunneum LRC112 (176) followed by A. obscurus x M. brunneum F52 (212), A. lineatus x M. brunneum LRC112 (215), and A. lineatus x M. brunneum F52 (292). Hypothetical calculations showed that M. brunneum exposure earlier in the season resulted in a longer LT50 but the earliest LT50 calendar date. Later M. brunneum exposure dates resulted in lower LT50’s, but later LT50 dates. This conceptual work demonstrates the importance of considering daily temperature oscillations, seasonality, and degree days in predicting the efficacy of entomopathogens to manage agricultural pests.

[IN1339] Managing Wireworms in Florida Sweet Potatoes

This publication describes current methods for managing wireworms in sweet potato. Wireworms, the larvae of click beetles, are the most damaging insect pests of those that infest the foliage and roots. Soil tillage and crop rotation can suppress populations of these root pests but adequate management requires diligent surveillance and the use of insecticides. Describes new research on managing wireworms with alternative insecticide active ingredients and entomopathogenic nematodes.

Assessment of the Attraction Range of Sex Pheromone Traps to Agriotes (Coleoptera, Elateridae) Male Click Beetles in South-Eastern Europe

The attraction range of YATLORf pheromone traps to adults of four species of Agriotes (A. brevis, A. sordidus, A. litigiosus, and A. ustulatus) was studied to provide additional information about the most harmful Agriotes species in Europe. Male click beetles were marked and released at different distances from a pheromone trap. The recapture rate was calculated and analyzed using analysis of variance. The recapture rate was significantly affected by distance, species, and wind direction. The recapture rate decreased as distance increased. The majority of beetles were caught from short distances (up to 10 m) within the first five days. A. brevis, a mainly crawling species, showed the lowest recapture rate. The wind direction affected the recovery rate, with a significantly lower number of beetles moving downwind from the release points. Maximum sampling ranges and effective sampling areas were calculated. The obtained estimations were low (53 to 86 m and 509 to 2602 m2, respectively) for all the considered Agriotes species, suggesting that they were unsuitable for use as mass trapping instruments to disrupt mating. However, it seems possible to use the traps not only as monitoring tools, but also as attract-and-kill strategies for most beetle populations.

Wireworms in Florida Sugarcane

Wireworms, the larval stage of a click beetle, often cause severe damage to numerous crops in Florida. At least twelve species of wireworms have been found in southern Florida, but only the corn wireworm, Melanotus communis, is considered to cause significant economic damage to sugarcane. Since M. communis is the important wireworm species, the rest of this document will pertain to this species. Generally, wireworms are a pest of newly planted sugarcane and only rarely a pest in ratoon sugarcane. More studies are needed, but the current information suggests substantial percentages (e.g. 40% or more) of wireworms could be killed by flooding but, in general, the flood duration had to be at least 4 to 5 weeks at water temperatures above 24 °C. Soil insecticides are generally used in newly planted sugarcane for wireworm control. Insecticides are not used for wireworm control in ratoon sugarcane. Pheromone traps are untested in Florida sugarcane for click beetles but have an important function in for both mass trapping and monitoring in other agricultural systems.

Primerjava tradicionalnih in sodobnih metod za določanje gospodarsko pomembnih vrst strun (Coleoptera: Elateridae)

<p>Wireworms are larvae of click beetles (Coleoptera: Elateridae) and are well known pests of economic importance. Knowing the species diversity in a particular area is important, as the ecological requirements and consequent management strategies of individual species vary. Morphological identification of wireworms is challenging; separating between individual species is often almost impossible. Molecular methods therefore complement morphological methods. Mitochondrial gene for cytochrome oxidase I is most commonly used for molecular identification of wireworms. In this study we list molecular, morphological and behavioural methods for wireworm identification and also highlight the advantages and disadvantages of these methods. At the end of the article, a simplified morphological identification key for determining economically important wireworm species of the genus <em>Agriotes</em> in Slovenian language is attached.</p>

The status of Elateridae (Coleoptera) in India

Beetles are a group of insects that form the order Coleoptera, in the superorder Endopterygota. It is estimated that a quarter of all described species in the world belongs to this order. The family Elateridae or click beetles is the ninth-largest family under this order. Wireworms are the larval stage of this family and they play a role in the ecosystem as they are omnivorous and act as pests. There are over 800 species of elaterids recorded from the Indian Subcontinent under eight subfamilies. India is rich in floral and faunal diversity and insect diversity in particular constitute about 6% of all identified insects in the world with a large number being endemic species. But in contrast to its extreme species richness, there is comparatively very little knowledge about this family of beetles when compared to other families. And as such, there is still a lot of potential to study its ecology and diversity. It is also because of this same reason that review of the status of the elaterid family is being done as a prequel to the actual field study.