A hypothesis to explain accuracy of wasp resemblances

Mimicry is one of the oldest concepts in biology, but it still presents many puzzles and continues to be widely debated. Simulation of wasps with a yellow-black abdominal pattern by other insects (commonly called “wasp mimicry”) is traditionally considered a case of resemblance of unprofitable by profitable prey causing educated predators to avoid models and mimics to the advantage of both (Figure 1a). However, as wasps themselves are predators of insects, wasp mimicry can also be seen as a case of resemblance to one's own potential antagonist. We here propose an additional hypothesis to Batesian and Müllerian mimicry (both typically involving selection by learning vertebrate predators; cf. Table 1) that reflects another possible scenario for the evolution of multifold and in particular very accurate resemblances to wasps: an innate, visual inhibition of aggression among look-alike wasps, based on their social organization and high abundance. We argue that wasp species resembling each other need not only be Müllerian mutualists and that other insects resembling wasps need not only be Batesian mimics, but an innate ability of wasps to recognize each other during hunting is the driver in the evolution of a distinct kind of masquerade, in which model, mimic, and selecting agent belong to one or several species (Figure 1b). Wasp mimics resemble wasps not (only) to be mistaken by educated predators but rather, or in addition, to escape attack from their wasp models. Within a given ecosystem, there will be selection pressures leading to masquerade driven by wasps and/or to mimicry driven by other predators that have to learn to avoid them. Different pressures by guilds of these two types of selective agents could explain the widely differing fidelity with respect to the models in assemblages of yellow jackets and yellow jacket look-alikes

Increased Resin Collection after Parasite Challenge: A Case of Self-Medication in Honey Bees?

The constant pressure posed by parasites has caused species throughout the animal kingdom to evolve suites of mechanisms to resist infection. Individual barriers and physiological defenses are considered the main barriers against parasites in invertebrate species. However, behavioral traits and other non-immunological defenses can also effectively reduce parasite transmission and infection intensity. In social insects, behaviors that reduce colony-level parasite loads are termed “social immunity.” One example of a behavioral defense is resin collection. Honey bees forage for plant-produced resins and incorporate them into their nest architecture. This use of resins can reduce chronic elevation of an individual bee's immune response. Since high activation of individual immunity can impose colony-level fitness costs, collection of resins may benefit both the individual and colony fitness. However the use of resins as a more direct defense against pathogens is unclear. Here we present evidence that honey bee colonies may self-medicate with plant resins in response to a fungal infection. Self-medication is generally defined as an individual responding to infection by ingesting or harvesting non-nutritive compounds or plant materials. Our results show that colonies increase resin foraging rates after a challenge with a fungal parasite (Ascophaera apis: chalkbrood or CB). Additionally, colonies experimentally enriched with resin had decreased infection intensities of this fungal parasite. If considered self-medication, this is a particularly unique example because it operates at the colony level. Most instances of self-medication involve pharmacophagy, whereby individuals change their diet in response to direct infection with a parasite. In this case with honey bees, resins are not ingested but used within the hive by adult bees exposed to fungal spores. Thus the colony, as the unit of selection, may be responding to infection through self-medication by increasing the number of individuals that forage for resin

Self-Medication as Adaptive Plasticity: Increased Ingestion of Plant Toxins by Parasitized Caterpillars

Self-medication is a specific therapeutic behavioral change in response to disease or parasitism. The empirical literature on self-medication has so far focused entirely on identifying cases of self-medication in which particular behaviors are linked to therapeutic outcomes. In this study, we frame self-medication in the broader realm of adaptive plasticity, which provides several testable predictions for verifying self-medication and advancing its conceptual significance. First, self-medication behavior should improve the fitness of animals infected by parasites or pathogens. Second, self-medication behavior in the absence of infection should decrease fitness. Third, infection should induce self-medication behavior. The few rigorous studies of self-medication in non-human animals have not used this theoretical framework and thus have not tested fitness costs of self-medication in the absence of disease or parasitism. Here we use manipulative experiments to test these predictions with the foraging behavior of woolly bear caterpillars (Grammia incorrupta; Lepidoptera: Arctiidae) in response to their lethal endoparasites (tachinid flies). Our experiments show that the ingestion of plant toxins called pyrrolizidine alkaloids improves the survival of parasitized caterpillars by conferring resistance against tachinid flies. Consistent with theoretical prediction, excessive ingestion of these toxins reduces the survival of unparasitized caterpillars. Parasitized caterpillars are more likely than unparasitized caterpillars to specifically ingest large amounts of pyrrolizidine alkaloids. This case challenges the conventional view that self-medication behavior is restricted to animals with advanced cognitive abilities, such as primates, and empowers the science of self-medication by placing it in the domain of adaptive plasticity theory

Attraction of Gabonia and Nzerekorena to pyrrolizidine alkaloids - with descriptions of 13 new species and notes on male structural peculiarities

: Attraction of Gabonia and Nzerekorena to pyrrolizidine alkaloids -with descriptions of 13 new species and notes on male structural peculiarities (Insect, Coleoptera, Chrysomelidae, Alticinae). -Spixiana 20/1: 7-38 Baits containing pyrrolizidine alkaloids (PAs) attracted 17 species of Gabonia and 1 of Nzerekorena in Kenya, East Africa. In Gabonia attraction is strongly male-biased (> 2600 ❹❹ vs 27 ➁➁). Attempts to discover the beetles' hostplants were unsuccessful, but hosts of several other Coleoptera were recorded, including that of 1 Gabonia species not attracted to PAs. In addition to field-observations, the paper provides descriptions of 13 new species (12 Gabonia and 1 Nzerekorena), keys to the species, and a morphological characterization of peculiar structures in males

FIGURE 51‒54 in Gloora gen. nov. (Lepidoptera: Erebidae: Arctiinae: Arctiini: Ctenuchina) for several Agylla - like Arctiinae

FIGURE 51‒54. Gloora alba comb. nov. (51), G. mundula comb. nov. (52), G. sericea comb. nov. (53), G. canae sp. nov. (54), female genitalia (bursae). Scale bars: 1 mm

Gloora gen. nov. (Lepidoptera: Erebidae: Arctiinae: Arctiini: Ctenuchina) for several Agylla - like Arctiinae

Grados, Juan, Laguerre, Michel, Boppré, Michael (2018): Gloora gen. nov. (Lepidoptera: Erebidae: Arctiinae: Arctiini: Ctenuchina) for several Agylla - like Arctiinae. Zootaxa 4497 (2): 226-240, DOI: 10.11646/zootaxa.4497.2.

FIGURES 15‒30 in Gloora gen. nov. (Lepidoptera: Erebidae: Arctiinae: Arctiini: Ctenuchina) for several Agylla - like Arctiinae

FIGURES 15‒30. Gloora alba comb. nov. (15‒18), G. mundula comb. nov. (19‒22), G. sericea comb. nov. (23‒26), and G. canae sp. nov. (27‒30), habitus male (15, 16, 19, 20, 23, 24, 27, 28) and female (17, 18, 21, 22, 25, 26, 29, 30), dorsal (left) and ventral (right) view. Scale bar: 5 mm