TY  - JOUR
A1  - Moustafa, Moataz A. M.
A1  - Fouad, Eman A.
A1  - Ibrahim, Emad
A1  - Erdei, Anna Laura
A1  - Kárpáti, Zsolt
A1  - Fónagy, Adrien
T1  - The comparative toxicity, biochemical and physiological impacts of chlorantraniliprole and indoxacarb on Mamestra brassicae (Lepidoptera: Noctuidae)
JF  - Toxics
N2  - Background: The cabbage moth, Mamestra brassicae, is a polyphagous pest that attacks several crops. Here, the sublethal and lethal effects of chlorantraniliprole and indoxacarb were investigated on the developmental stages, detoxification enzymes, reproductive activity, calling behavior, peripheral physiology, and pheromone titer of M. brasssicae. Methods: To assess pesticide effects, the second instar larvae were maintained for 24 h on a semi-artificial diet containing insecticides at their LC\(_{10}\), LC\(_{30}\), and LC\(_{50}\) concentrations. Results: M. brassicae was more susceptible to chlorantraniliprole (LC\(_{50}\) = 0.35 mg/L) than indoxacarb (LC\(_{50}\) = 1.71 mg/L). A significantly increased developmental time was observed with both insecticides at all tested concentrations but decreases in pupation rate, pupal weight, and emergence were limited to the LC50 concentration. Reductions in both the total number of eggs laid per female and the egg viability were observed with both insecticides at their LC\(_{30}\) and LC\(_{50}\) concentrations. Both female calling activity and the sex pheromone (Z11-hexadecenyl acetate and hexadecenyl acetate) titer were significantly reduced by chlorantraniliprole in LC\(_{50}\) concentration. Antennal responses of female antennae to benzaldehyde and 3-octanone were significantly weaker than controls after exposure to the indoxocarb LC\(_{50}\) concentration. Significant reductions in the enzymatic activity of glutathione S-transferases, mixed-function oxidases, and carboxylesterases were observed in response to both insecticides.
KW  - toxicity
KW  - sublethal effects
KW  - chlorantraniliprole
KW  - indoxacarb
KW  - Mamestra brassicae
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-303931
SN  - 2305-6304
VL  - 11
IS  - 3
ER  - 
TY  - JOUR
A1  - Vikuk, Veronika
A1  - Fuchs, Benjamin
A1  - Krischke, Markus
A1  - Mueller, Martin J.
A1  - Rueb, Selina
A1  - Krauss, Jochen
T1  - Alkaloid Concentrations of Lolium perenne Infected with Epichloë festucae var. lolii with Different Detection Methods—A Re-Evaluation of Intoxication Risk in Germany?
JF  - Journal of Fungi
N2  - Mycotoxins in agriculturally used plants can cause intoxication in animals and can lead to severe financial losses for farmers. The endophytic fungus Epichloë festucae var. lolii living symbiotically within the cool season grass species Lolium perenne can produce vertebrate and invertebrate toxic alkaloids. Hence, an exact quantitation of alkaloid concentrations is essential to determine intoxication risk for animals. Many studies use different methods to detect alkaloid concentrations, which complicates the comparability. In this study, we showed that alkaloid concentrations of individual plants exceeded toxicity thresholds on real world grasslands in Germany, but not on the population level. Alkaloid concentrations on five German grasslands with high alkaloid levels peaked in summer but were also below toxicity thresholds on population level. Furthermore, we showed that alkaloid concentrations follow the same seasonal trend, regardless of whether plant fresh or dry weight was used, in the field and in a common garden study. However, alkaloid concentrations were around three times higher when detected with dry weight. Finally, we showed that alkaloid concentrations can additionally be biased to different alkaloid detection methods. We highlight that toxicity risks should be analyzed using plant dry weight, but concentration trends of fresh weight are reliable.
KW  - Epichloë
KW  - Lolium perenne
KW  - toxicity
KW  - grasslands
KW  - HPLC/UPLC methods
KW  - endophyte
KW  - plant fresh/dry weight
KW  - alkaloid detection methods
KW  - mycotoxins
KW  - phenology
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-213171
SN  - 2309-608X
VL  - 6
IS  - 3
ER  - 
TY  - JOUR
A1  - Krauss, Jochen
A1  - Vikuk, Veronika
A1  - Young, Carolyn A.
A1  - Krischke, Markus
A1  - Mueller, Martin J.
A1  - Baerenfaller, Katja
T1  - Epichloë endophyte infection rates and alkaloid content in commercially available grass seed mixtures in Europe
JF  - Microorganisms
N2  - Fungal endophytes of the genus Epichloë live symbiotically in cool season grass species and can produce alkaloids toxic to insects and vertebrates, yet reports of intoxication of grazing animals have been rare in Europe in contrast to overseas. However, due to the beneficial resistance traits observed in Epichloë infected grasses, the inclusion of Epichloë in seed mixtures might become increasingly advantageous. Despite the toxicity of fungal alkaloids, European seed mixtures are rarely tested for Epichloë infection and their infection status is unknown for consumers. In this study, we tested 24 commercially available seed mixtures for their infection rates with Epichloë endophytes and measured the concentrations of the alkaloids ergovaline, lolitrem B, paxilline, and peramine. We detected Epichloë infections in six seed mixtures, and four contained vertebrate and insect toxic alkaloids typical for Epichloë festucae var. lolii infecting Lolium perenne. As Epichloë infected seed mixtures can harm livestock, when infected grasses become dominant in the seeded grasslands, we recommend seed producers to test and communicate Epichloë infection status or avoiding Epichloë infected seed mixtures.
KW  - Epichloë spp.
KW  - grass endophytes
KW  - cool-season grass species
KW  - infection rates
KW  - alkaloids
KW  - toxicity
KW  - livestock
KW  - horses
KW  - Lolium perenne
KW  - perennial ryegrass
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-203323
SN  - 2076-2607
VL  - 8
IS  - 4
ER  - 
TY  - JOUR
A1  - Schneider, Christof W.
A1  - Tautz, Jürgen
A1  - Grünewald, Bernd
A1  - Fuchs, Stefan
T1  - RFID Tracking of Sublethal Effects of Two Neonicotinoid Insecticides on the Foraging Behavior of Apis mellifera
JF  - PLoS One
N2  - The development of insecticides requires valid risk assessment procedures to avoid causing harm to beneficial insects and especially to pollinators such as the honeybee Apis mellifera. In addition to testing according to current guidelines designed to detect bee mortality, tests are needed to determine possible sublethal effects interfering with the animal's vitality and behavioral performance. Several methods have been used to detect sublethal effects of different insecticides under laboratory conditions using olfactory conditioning. Furthermore, studies have been conducted on the influence insecticides have on foraging activity and homing ability which require time-consuming visual observation. We tested an experimental design using the radiofrequency identification (RFID) method to monitor the influence of sublethal doses of insecticides on individual honeybee foragers on an automated basis. With electronic readers positioned at the hive entrance and at an artificial food source, we obtained quantifiable data on honeybee foraging behavior. This enabled us to efficiently retrieve detailed information on flight parameters. We compared several groups of bees, fed simultaneously with different dosages of a tested substance. With this experimental approach we monitored the acute effects of sublethal doses of the neonicotinoids imidacloprid (0.15-6 ng/bee) and clothianidin (0.05-2 ng/bee) under field-like circumstances. At field-relevant doses for nectar and pollen no adverse effects were observed for either substance. Both substances led to a significant reduction of foraging activity and to longer foraging flights at doses of >= 0.5 ng/bee (clothianidin) and >= 1.5 ng/bee (imidacloprid) during the first three hours after treatment. This study demonstrates that the RFID-method is an effective way to record short-term alterations in foraging activity after insecticides have been administered once, orally, to individual bees. We contribute further information on the understanding of how honeybees are affected by sublethal doses of insecticides.
KW  - memory
KW  - nicotinic acetylcholine-receptors
KW  - unpaired median neurons
KW  - honey bees
KW  - learning performances
KW  - toxicity
KW  - hymenoptera
KW  - pesticides
KW  - relevance
KW  - agonist
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-131753
VL  - 7
IS  - 1
ER  -