SpiDivERse

Introduction

The SpiDivERse (Spider Diversity and Evolutionary Research) workgroup aims to increase understanding on the diversity and distributions of one of the planets most fascinating taxonomic groups, the hyperdiverse Araneae (spiders).

Spiders are a hyperdiverse taxon with almost 50,000 described species, and predictions are that their true diversity may be three or more times that number. They are a dominant group of arthropod predators in all ecosystems and their assemblages are often highly diverse in even homogenous anthropic habitats, in the tropics their diversity is astounding.

In order to achieve our primary aim, we plan to identify, catalogue and describe spider communities from some of the most imperilled and biodiverse regions on earth. We are especially interested in species discoveries and descriptive taxonomy. With an aim of fostering taxonomic expertise in this group and training enthusiastic members from processing and identifying batches of samples through to descriptive taxonomic papers (i.e. description of new species) and regional checklists.

For most of the world, however, our knowledge of the diversity of spiders is imperfect, deficient or negligible.
Paul A. Selden

Initially formed by Brogan L Pett (Research director) and Jaime Escobar-Toledo in 2021. Current active members/researchers include Katie Murray (Data manager), Indigo Pai-Gibson (doubling up as Illustrator), Barti Baszczowski (Radboud University), John McCullough (Bangor University) Alex Wright, Rafael Santos and Rebecca Saxton (all from the University of Exeter’s Penryn campus).

Join us!

Current projects

 Mariarano forest – Madagascar

 2020 – now  

 Brogan Pett, Jaime Escobar-Toledo, Katie Murray, Mamitiana Rakotorahalahy, Soopi, John McCullough, Bartosz Baszczowski

 Publications

This long-term SpiDiverse project/fieldsite has been ongoing in boreal summers (June-August) through 2017, 2018 and then 2023 onwards for at least the next five years (til 2028). Our primary goal is to document the spider diversity of this area of enigmatic dry deciduous forest in north-western Madagascar, in partnership with Operation Wallacea. In order to achieve our primarily goal, we aim to catalogue and illustrate all species, describing any taxa unknown to science. The study site lies in the Mahajanga region, falling within the northwestern dry deciduous forest ecoregion, often overlooked in favour of rainforests closer to Tana. As such, understanding of the biodiversity of these forests here is very poor.

We have currently identified >220 morphospecies, describing seven (published) new species in the process, with >50 new species awaiting description and in the pipeline, all discovered for the first time during the course of this inventory.

Starting in 2024, we have employed a new systematic sampling regime to analyse community ecology and functional diversity changes between different land-use systems in the area. This new element of the project aims to understand and quantify the threats facing spiders (and thus biodiversity more generally). By analysing spider communities across broad-scale habitat types (a spectrum from interior forest to rice paddies), and extracting functional diversity metrics from these, we hope to increase understanding on this completely neglected area of Madagascar. We hope to use this information to (i) categorise indicator species for both intact forest systems and of environmental degradation, (ii) test the indicator value of these species in a multi-taxa framework by assessing identified species’ ability to predict abundance and diversity of higher taxa (e.g. lemurs, reptiles, birds), (iii) present the first standardised community dataset of spiders across different land- use categories in Madagascar. (iv) serve as the first time-series of spiders in Madagascar by analysing key species abundance trends over time, (v) analyse niche space reduction under deforestation and conversion through functional diversity analyses between habitats.

Mariarano is undoubtedly the flagship project of SpiDiverse, where the combination of our ecological, functional and systematic projects have potential to make this site one of the best studied tropical African systems for spider diversity.

 Salonga National Park, D.R. Congo

 2022 – now  

 Brogan Pett, Menard Mbende, Dieu Merci Mpongo Iyomi

 Publications

We participated in and conducted a rapid biodiversity inventory of several sites in Salonga National Park (Africa’s largest rainforest reserve; link to report) in November/December 2022, being the first researchers to publish a single spider record from Africa’s largest rainforest reserve. Whilst we amassed several hundred species and have begun publishing new species from here with Congolese colleagues, e.g. a new ant-mimicking jumping spider Myrmarachne salongensis Pett, 2024 and three new Thiratoscirtus Simon, 1886, this is surely a multi-year project that will take quite some time to finish the IDs.

 Makira forest – northeastern Madagascar

 2020 – now  

 Brogan Pett, Indigo Pai-Gibson, Katie Murray, Rebecca Saxton, Alex Wright, Rafael Santos

We participated in the Makira expedition with the aim to rediscover around a dozen spiders not recorded since their descriptions >50 years ago and discover new species from this very understudied forest region. The Makira report is found here: xxx. Despite horrendous weather (one single sunny day and the rest torrential rain) we found many exciting new species and genera, as well as half a dozen “rediscoveries”.

 Sinoe County – southern Liberia

 2024 – now  

 Brogan Pett

 Publications

As collaborators on the Sustainable Oil Palm in West Africa (SOPWA) project, we sorted and identified all the spiders from a couple years of pitfall trapping and aerial sampling from several sites distributed around southern Liberia. The project aims to understand the community ecological and functional responses to land use change, comparing natural rainforest, community palm and oil palm systems. We discovered distinct spider communities in each habitat, and a decrease in species diversity on a gradient from rainforest to oil palm, with rainforests holding the most species. ~ 200 species have been identified in total and several have already been described as new to science. This ongoing project forms a fantastic collaboration with researchers from Liberia, Finland, Belgium, Iceland and the U.K.

Collaborators

Rudy Jocqué – Royal Museum for Central Africa (RMCA)
Arnaud Henrard – Royal Museum for Central Africa (RMCA)
Mark Alderweireldt – Ghent University