Pollination Contribution Differs among Insects Visiting Cardiocrinum cordatum Flowers

(1) Background: Cardiocrinum cordatum (Thunb.) Makino (Liliaceae) is a forest perennial herb distributed in East Asia. Although flower visitors for this plant species have been well reported, their contribution to pollination remains unknown. (2) Methods: We evaluated pollination contribution for visitors of C. cordatum flowers in a natural cool temperate forest. We investigated visiting frequency, the number of pollen grains per body surface, fruit set, and the mean number of seeds per fruit produced after a single visit of each visiting species. Combining the results of these experiments, we determined the most important pollinators of this species. (3) Results: For the population investigated in the study, the three most essential pollinators were the bumblebee (Bombus diversus tersatus) (Apidae), sweat bee (Halictidae sp.), and marmalade hoverfly (Episyrphus balteatus) (Syrphidae). Additionally, we found that the contribution of a flower-visiting ant species (Myrmica ruginodis Nylander (s.l.)) (Formicidae) is small. (4) Conclusions: Pollinator contributions differed among flower visitors. Our results underscore the insufficiency of current information about flower-visiting species to evaluate pollination contribution.

ВИДОВИЙ СКЛАД КОМАХ-НЕКРОБІОНТІВ НА ДІЛЯНКАХ З РІЗНИМИ ТИПАМИ ҐРУНТІВ В ОКОЛИЦЯХ МІСТА ХАРКОВА (УКРАЇНА)

On corpses of animals in areas with different soil types, 34 species of insects from three orders and 14 families were found, among which Coleoptera (24 species) and Diptera (7 species) were registrated as dominants. The species composition of insect-necrobionts did not differ from each other in areas with different soil types (faunistic similarity by index of Chekanovsky-Sørensen – 0.66–0.78). Typical necrobionts (more than 80% of the species composition of all insects) are represented by the majority of Diptera (Calliphora vomitoria, C. vicina, Cynomyia mortuorum, Lucilia caesar, L. sericata, Fannia scalaris, Sarcophaga carnaria) and Coleoptera (Hister impressus, Saprinus semistriatus, Necrophorus fossor, Silpha obscura, Oiceptoma thoracica, Creophilus maxillosus, Thanatophilus sinuatus, Th. rugosus, Staphylinus caesareus, Creophilus maxillosus, Philonthus nitidus, Ph. addendus, Dermestes undulatus, D. frischi, D. olivieri, D. erichsoni, D. murinus, Necrobia ruficollis, N. rufipes, N. violacea, Omosita colon), among which there are both typical necrophagous and entomophagous. These species are of most practical importance in forensic entomology. Some species of beetles (Adalia bipunctata, Onthophagus coenobita, Stomis pumicatus, Tachinus humeralis) and ants (Lasius niger, Myrmica ruginodis) identified during the course of study can be attributed to the random entomofauna of the corpses (about 20% of the species composition of all Insecta).

Ants’ Ability in Solving Simple Problems

Aiming to know the extent of the ants’ cognitive abilities, we set Myrmica ruginodis workers in four problematic situations. We discovered that these ants could walk round a barrier, by foraging and navigating as usual, using known visual cues. They could walk preferentially on smooth substrates instead of rough ones, but did not memorize their choice. This behavior may be due to the easier deposit of pheromones on a smooth substrate. The ants could establish a single way when having only two narrow paths for going in and out of their nest. This was the consequence of the ants’ traffic and of the distinct pheromonal deposits while going in and out of the nest. The oldest ants needing sugar water could push a door for getting such water. They did so by having the audacity to go on walking, whatever the presence of a door. Such a door is not a tool sensu stricto. Future studies will examine if ants can lean new techniques, can use tools and/or can learn using tools.

Studies of Laboulbeniales (Fungi, Ascomycota) on Myrmica ants (II): variation of infection by Rickia wasmannii over habitats and time

One group of important insect parasites are the Laboulbeniales (Ascomycota), microscopic fungi that live attached to the exterior of their hosts, mainly beetles, but also mites, millipedes, earwigs, and ants. Rickia wasmannii is a common fungus in Europe and is limited to the ant genus Myrmica (Hymenoptera, Formicidae). This paper presents patterns of R. wasmannii infection in the Netherlands from three host species collected in three series of pitfall traps: Myrmica ruginodis, M. sabuleti, and M. scabrinodis. The infection rate of especially M. sabuleti was so high, that it allowed analyses of infection patterns over time and habitats. We found that only workers were infected, mostly the older ones with a hard cuticle. Gynes are probably never infected. This is supported with data from a nature restoration site: in this young area R. wassmannii is not abundant in contrast to close-by sites, so there probably is a build-up of infection by Rickia over time through worker contact. Taken over three periods throughout the year (spring, summer, autumn), parasite prevalence declined significantly in M. sabuleti, with a non-significant declining trend in M. scabrinodis. Increased allogrooming behavior in the nest in the winter may be the main contributing factor for this. New, largely uninfected cohorts of workers lead to decreased infection rate during the reproduction season. Finally, Rickia wasmannii occurs throughout a wide variety of habitats, from moist and cool to dry and warm.

Comparative outlook over physiological and ecological characteristics of three closely-related Myrmica species

This paper summarizes our findings on the eye morphology, visual perception, learning abilities, navigation system and recruitment strategy of three Myrmica species, pointing out the agreement between each species’ morphological, physiological and behavioral characters as well as the accordance between these characters and each species’ environmental preferences. We also draw biological generalities and report other similar studies. Myrmica sabuleti workers have small eyes, perceive the dimension, number of basic elements and orientation of a visual cue but do not distinguish shapes from one another. They see the colors, perceive UV light and the perspective, and adapt their vision to the light intensity. They learn odors better than visual cues and essentially use odors to navigate. Myrmica ruginodis workers have large eyes, distinguish shapes, small see-through forms as well as patterns of luminous points located above them. They have no olfactory memory but a very long lasting visual one. They exclusively use visual cues located above them while travelling, relying on odors only when they no longer see. Myrmica rubra workers have eyes of middle size and distinguish filled shapes but not hollow forms. Their olfactory and visual conditioning lead to equivalent learning in the course of time and they use all available olfactory and visual elements for navigating.

The visual perception of the ant Myrmica ruginodis (Hymenoptera: Formicidae)

Myrmica ruginodis workers are able to distinguish black or white circles from black or white squares, black or white ellipses from black or white rectangles as well as hollow circles or ellipses from hollow squares or rectangles. They can also distinguish differently oriented elements as well as objects containing a various number of elements. These workers are also able to perceive and discriminate transparent cues on a black background and even small luminous spots on a black ceiling. Such visual abilities are in agreement with the species’ eye morphology and system of navigation: the eyes are rather large with a well-developed posterio-dorsal part, and the foragers rely exclusively on cues located above them, neglecting odorous elements as long as visual perception is possible. Probably, they might use cues located in the canopy and the sky to travel in certain circumstances.

Chemical properties of forest soils as affected by nests of Myrmica ruginodis (Formicidae)

Chemical properties (total and available P concentration; oxidizable C concentration; available K, Na, and Ca concentration; and pH) were quantified for 33 nests of the ant Myrmica ruginodis and in surrounding soil in young spruce forest stands. All properties, except total P, were significantly higher in the nests than in the surrounding soil. Total P was not higher in nests than in surrounding soil across all nests because nests had higher total P than surrounding soil if the soil contained low concentrations of total P but nests had lower total P than surrounding soil if the soil contained high concentrations of total P. The effect of nests on total P in the surrounding soil corresponded with effects of nests on oxidizable carbon (an indicator of organic matter) in the surrounding soil (concentrations of oxidizable carbon and total P were closely correlated). Available P concentrations were much higher in nests than in surrounding soil. Overall, the results indicated that two main processes explain the chemical changes of soil in the ant nests: (i) mixing due to excavation of deeper soil layers and (ii) deposition of excreta and food residues. The effect of soil mixing (whereby ants transport mineral soil from deeper layers to layers near the surface) is more pronounced in soils with high organic content near the surface because mixing increases the proportion of mineral soil in the nest while decreasing the proportion of organic matter and the concentration of total P.