Browsing by Person "Hiller, Thomas"

Now showing 1 - 2 of 2

Do biotic and abiotic factors influence the prevalence of a common parasite of the invasive alien ladybird Harmonia axyridis?
(2022) Haelewaters, Danny; Hiller, Thomas; Ceryngier, Piotr; Eschen, René; Gorczak, Michał; Houston, Makenna L.; Kisło, Kamil; Knapp, Michal; Landeka, Nediljko; Pfliegler, Walter P.; Zach, Peter; Aime, M. Catherine; Nedvěd, Oldřich
Hesperomyces virescens (Ascomycota, Laboulbeniales), a fungal ectoparasite, is thus far reported on Harmonia axyridis from five continents: North and South America, Europe, Africa, and Asia. While it is known that He. virescens can cause mortality of Ha. axyridis under laboratory conditions, the role of biotic and abiotic factors in influencing the distribution of He. virescens in the field is unknown. We collected and screened 3,568 adult Ha. axyridis from 23 locations in seven countries in Central Europe between October and November 2018 to test the effect of selected host characters and climate and landscape variables on the infection probability with He. virescens. Mean parasite prevalence of He. virescens on Ha. axyridis was 17.9%, ranging among samples from 0 to 46.4%. Host sex, climate, and landscape composition did not have any significant effect on the infection probability of He. virescens on Ha. axyridis. Two color forms, f. conspicua and f. spectabilis, had a significantly lower parasite prevalence compared to the common Ha. axyridis f. novemdecimsignata.
Enhanced crop diversity but not smaller field size benefit bats in agricultural landscapes
(2025) Hiller, Thomas; Gall, Friederike; Grass, Ingo; Hiller, Thomas; Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany; Gall, Friederike; Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany; Grass, Ingo; Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany
Context: Farmland biodiversity continues to decline due to the expansion and intensification of agriculture. Historically, efforts to conserve farmland biodiversity have focused on conserving habitats outside agricultural production areas. More recently, attention has turned to the conservation potential of the cropland matrix, where reducing field size and increasing crop diversity to promote crop heterogeneity can significantly benefit farmland biodiversity. Bats are one group of farmland species that have experienced dramatic declines over recent decades. Objectives: Here we investigated the effects of crop heterogeneity (crop diversity, field size) and landscape structural elements (e.g. length of linear structures, distance to forest, proportion of semi-natural habitat) on the activity of bat functional groups. Results: Increasing crop diversity led to greater bat activity, especially for open space foraging bats. However, contrary expectations, bat activity was not affected by heterogeneity in crop configuration, i.e. field edge density. Furthermore, structural landscape elements, including hedgerows and distance to forest, were important predictors of bat activity, especially for species that hunt in highly cluttered spaces. While crop diversity clearly benefited bat activity, the lack of effect of crop configurational heterogeneity on bat foraging activity may suggest heterogeneityarea trade-offs and intensive pesticide use in small-scale vegetable production. Conclusions: Therefore, in addition to maintaining high levels of crop diversity, promoting hedgerows and tree lines between farmland and woodland may facilitate bat activity across the agricultural landscape matrix. The combination of high crop heterogeneity and structural elements provides favorable hunting grounds for bats and may promote their conservation in agricultural landscapes.