Caddis 2018

Once I'd made the decision that I was never going to be Dipterist, life got much easier. Not that there's anything wrong with Dipterists, in fact, some of my best friends are... We are very lucky in VC55 in having a very knowledgable and approachable expert in Ray Morris, who is always happy to receive caddis flies from moth traps, so I have outsourced my caddis I.D.s to Ray who has kindly provided the following list for my 2018 trapping efforts (30W Actinic + 15W Synergetic). Ray tells me that this haul is fairly average for a suburban garden, but as with moths, it can be surprising what turns up even in the middle of a town/city.

Ray Morris (2013) Provisional status of Trichoptera (caddis flies) in Leicestershire & Rutland (VC55). LESOPS 29 (February 2013)
ISSN 0957-1019. https://www.naturespot.org.uk/sites/default/files/downloads/LESOPS029_Caddis.pdf

Tool use in ants

Ants not only use tools but select the best tools for the task.

Humans use tools. Chimpanzees use tools. And it turns out ants use tools too, in a surprisingly sophisticated way:

When encountering liquid food sources, ants of the genus Aphaenogaster drop various materials as tools into the food, and then carry the food-soaked tools back to the nest. Although this is one of the well-documented examples of tool use in insects, we know little about which factors influence their choice of tools during foraging. Here, we investigated the tool-using behavior of Aphaenogaster subterranea by examining, across a range of settings, how tool-using workers deal with various foraging challenges. We used different types of tools and liquid baits with varying distances between the baits and the tools piled around them. Although ants showed the strongest preference for the most easily transportable tools, the frequency of usage of the less preferred larger tools increased when these were the first to be discovered or were more readily accessible to the ants. Additionally, tool selection occurred at 2 stages: when tools were picked up and dropped into baits, and later, when food-soaked tools were retrieved from baits. Our results confirm that tool use in A. subterranea exhibits a high degree of flexibility. Ants seem to be able not only to optimize their foraging effort by selecting tools that are best matched to the particular foraging environment, but also to learn how to improve the use of certain tools by modifying them. The adaptive value of flexibility in tool use may be the increased efficiency in the utilization of liquid food sources, which gains importance in the light of competition with co-occurring ant species.

Lőrinczi et al (2018) Which tools to use? Choice optimization in the tool-using ant, Aphaenogaster subterranea. Behavioral Ecology, 29(6), 1444-1452. https://doi.org/10.1093/beheco/ary110

Woodlice in the city - landscape scale conservation in miniature

The latest issue of ZooKeys is a special edition: Isopods in a Changing World, containing papers from the 10th Symposium on the Biology of Terrestrial Isopods held in Budapest in 2017. The whole thing is well worth a look but three of the papers particularly captured my attention. Landscape scale conservation is a hot topic in ecology right now, however these papers look at the influence of small urban patches on isopod diversity and conservation.

Species compositions of terrestrial isopods in public parks of a commuter town in Japan https://doi.org/10.3897/zookeys.801.21875
This paper examines the isopods in 150 public parks in Munakata City in Japan. Eleven species of terrestrial isopods were present, of which seven were native or oriental species, and four exotic species originally distributed in the Mediterranean and European regions. The study showed that the urban public parks surrounded by forests or semi-natural environments provide habitats for native terrestrial isopods - native species tended to be located adjacent to natural environments adjacent to the parks, while their distributions had little relationship with the local environments within the park. The location of urban parks is an important factor to consider in their design to protect the largest number of species of native species - not something that usually gets much attention.

The role of urban forest patches in maintaining isopod diversity (Oniscidea) https://doi.org/10.3897/zookeys.801.22829
This paper assessed terrestrial isopod communities in degraded urban forest patches in a metropolitan area of Budapest, Hungary. The degree of urban disturbance was expressed using an urbanisation index based on built-up density and vegetation cover. Urbanisation indirectly affected the composition of isopod assemblages through the quantity of dead wood and soil plasticity. Urban forest patches harboured habitat generalist and established introduced species with relatively few rare endemic species. Areas with no or low anthropogenic disturbance had stable native species assemblages that were characteristic of rural sites in the same region. A bit of urban forest is definitely better than no forest, but not as valuable as an undisturbed environment.

Terrestrial isopods in urban environments: an overview https://doi.org/10.3897/zookeys.801.29580
In 2008 humans reached a major milestone: more than 50% of the global population now lives in cities (United Nation Population Division, World Urbanization Prospects 2011) - urbanization has become the major type of land use change in the 21st century. Terrestrial isopods are common members of the soil fauna in cities. They are well established in the built environment and in all types of urban green spaces including remnant habitat patches, parks, residential yards, vacant lots, and greenhouses. Urban isopod assemblages are a mixture of a few cosmopolitan species that thrive in human dominated landscapes, a subset of the native fauna, and more recently introduced species. This paper reviews studies of urban isopods, looks at current knowledge gaps and future research needs, and calls for a better global dataset, long term monitoring of urban populations.

The Evolution of True Bugs

The Order Hemiptera - True Bugs - contain a major proportion of insect diversity - over 120,000 described species including shieldbugs, plant bugs, bed bugs, pondskaters, cicadas, water bugs, aphids and scale insects. A recent scientific paper takes a shot at a DNA taxonomy for this diverse group. The researchers examined the DNA sequences of 2,395 genes from 193 groups. Unless you're into DNA taxonomy, the details of the paper are hard going, but the conclusions are fascinating. In summary:

• The bugs split from the Paleoptera (dragonflies, damselflies, and mayflies) and Neoptera (all other insects) 437 million years ago, before the Carboniferous period. This great age helps to explain the diversity and species richness of this group.
• Thrips (Thysanoptera) are the closest living relatives of true bugs and allies (Hemiptera).
• The results agree with evidence from the fossil record that the earliest hemipteroids fed on detritus, pollen, fungi, or spores (as do most modern bark lice and thrips). Plant-fluid feeding probably coincided with the origin of Hemiptera and evolved independently in thrips.

Phylogenomics and the evolution of hemipteroid insects PNAS USA, 21 Nov 2018) https://doi.org/10.1073/pnas.1815820115