A new species of Urupelma Kaderka et al. 2023 from Peru (Araneae, Theraphosidae, Theraphosinae), and a new proposal of homologous keels

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  Figure 5. Urupelma pampas Kaderka et al. 2023, from Peru, Apurímac, Chincheros. Habitus of female (MUSM-ENT 0515867). Photo: Radan Kaderka. A new species of Urupelma Kaderka et al. 2023 from Peru (Araneae, Theraphosidae, Theraphosinae), and a new proposal of homologous keels Abstract A new Peruvian tarantula, Urupelma lamarensis sp. nov., from the Ayacucho Department, in south-central Peru, is herein described, diagnosed and illustrated. Homologous keels of male bulbs in Urupelma Kaderka et al. 2023 are revised and newly established, the generic diagnosis is modified, including diagnoses of single species using these characters. The female genitalia of Urupelma pampas Kaderka et al. 2023 is figured for the first time. The variability of female genitalia of U. veronicae Kaderka et al. 2023 is also shown for the first time.  Kaderka, R. (2026). A new species of Urupelma Kaderka et al. 2023 from Peru (Araneae, Theraphosidae, Theraphosinae), and a new proposal of homologous k...

Prey killing rate of a generalist predator may be enhanced by macronutrient manipulation

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Prey killing rate of a generalist predator may be enhanced by macronutrient manipulation

Abstract

Generalist arthropod predators forage not only to gain energy and nutrients, but also to obtain a balanced intake of macronutrients (the intake target). We test two opposite hypotheses concerning the predation rate of nutritionally imbalanced predators: It will increase (1) if the prey is rich in macronutrients that the predator is short of, or (2) if the prey is low in macronutrients that the predator is short of. We used the wolf spider Pardosa amentata (Clerck) as the predator and nutritionally manipulated Drosophila melanogaster Meigen as prey. We completed a full factorial experiment with eight treatment groups, in which we measured predation, consumption and prey utilization of high-protein (HP) and high-lipid (HL) flies by spiders that were previously treated with either HP- or HL-flies for two or six days. The results supported hypothesis 2. Whether spiders had been previously fed HP-or HL-flies, those that were tested against the same type of fly killed more than those tested against the opposite type of fly. A likely explanation for this result is that the predator will be unable to reach its macronutritional intake target by continued feeding on the same prey. It will stay nutritionally imbalanced and continue to catch prey in an attempt to redress its imbalance. In natural systems, predation rates may thus be increased by the widespread mismatch between predators’ nutritional demands and what is available in prey. In practical biological control, it suggests a beneficial effect of feeding the predator prior to release with the pest it is intended to control.

Toft, S., Albuquerque, C., Degn, N. et al. Prey killing rate of a generalist predator may be enhanced by macronutrient manipulation. BioControl (2024). https://doi.org/10.1007/s10526-024-10251-8