Beetles

Nederlands below

Two recently published studies document 35 new beetle species for the islands of Saba and St. Eustatius.  Even with these latest additions, it is still estimated that nearly three quarters of the beetle population is still unknown.  Beetles play a vital role in breaking down natural waste and keeping insects in check, both important roles especially for small Caribbean islands.

The lady beetle Cycloneda sanguinea. Credit: Jan-Joost Mekkes

Beetles represent some of the tiniest inhabitants of the Dutch Caribbean but play a critical role in the environment.  They work as tiny decomposers and are vital in recycling nutrients from dead leaves and natural waste back into the ground.  As predators, they can help keep insect populations in check, especially pests like caterpillars and aphids which can damage crops.  Furthermore, with over 350,000 species worldwide, beetles represent a fifth of all living organisms in the world and nearly 40% of described insects.

Taxonomic Impediment

Unfortunately, there is still a lot that researchers don’t know about the beetle populations of the northern Leeward Islands.  Dubbed the “taxonomic impediment”, this is due to the gap between the local taxonomic knowledge and a shortage of trained taxonomists in the region.  In fact, it is estimated that only about 10-20% of the known beetle species of the islands have been correctly identified to date.

New Records

The firefly Aspisoma ignitum, Boven National Park, St. Eustatius. Credit: Jan-Joost Mekkes

Two new studies worked to bridge this gap for the islands of Saba and St. Eustatius.  Between 2008 and 2020, three researchers visited Saba and recorded a total of 22 different beetle species.  Of these, 14 were new to Saba or confirmed previously provisional records and four were new to the Dutch Antilles.  With this new study, the total number of beetle species recorded on Saba is now around 100.

In 2020, one researcher on St. Eustatius was able to collect 46 beetle species, of which 21 were new to the island, including 15 which were new to the Dutch Antilles.  Adding to previous records, this now brings the total number of known beetle species for the island to 117, which researchers believe to be about a quarter of the number of species expected.

The weevil Trichobaris bridwelli, Oranjestad, St. Eustatius. Credit: Jan-Joost Mekkes

Report your sightings

Have you observed any beetles or other insects?

Currently, researcher Jan-Joost Mekkes (jayjaymekkes@hotmail.com) is on Sint Eustatius and Michiel Boeken (michiel.boeken@gmail.com) on Saba.  Please forward them your beetle and other insect sightings.

Or submit your sightings and photos directly yourself on the website www.Observation.org or download the free apps (iPhone (iObs) & Android (ObsMapp)).

Species reports by local communities and tourists are invaluable for nature conservation efforts to help increase public awareness and overall species protection. Besides, DCNA, Observation International and Naturalis Biodiversity Center are working together to develop on automated species identification app for your phone. Your uploaded photos are of great value to make this possible. For questions, please contact research@DCNAnature.org

Read more

You can find the completed list of the beetle species documented during these studies in the Dutch Caribbean Biodiversity Database.

https://www.dcbd.nl/document/results-entomological-collecting-trip-st-eustatius-coleoptera

https://www.dcbd.nl/document/two-small-beetle-collections-saba-coleoptera

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Nieuwe kevers ontdekt in het Nederlands Caribische gebied

Twee recent gepubliceerde studies documenteren 35 nieuwe keversoorten voor de eilanden Saba en St. Eustatius. Ondanks deze laatste toevoegingen wordt geschat dat nog bijna driekwart van de keverpopulatie onbekend is. Kevers spelen een cruciale rol bij het afbreken van natuurlijk afval en het onder controle houden van insecten, beide belangrijk voor de Caribische eilanden.

Het lieveheersbeestje Cycloneda sanguinea, F.D. Roosevelt Airport, St. Eustatius. Credit: Jan-Joost Mekkes

Kevers zijn een van de kleinste bewoners van het Nederlands Caribisch gebied maar spelen een cruciale rol in de natuur. Ze werken als kleine ontbinders en zijn van vitaal belang bij het recyclen van voedingsstoffen uit dode bladeren en brengen natuurlijk afval terug in de grond. Als roofdieren kunnen ze helpen insectenpopulaties onder controle te houden, met name plagen zoals rupsen en bladluizen die gewassen kunnen beschadigen. Bovendien vertegenwoordigen kevers, met meer dan 350.000 soorten wereldwijd, een vijfde van alle levende organismen in de wereld en bijna 40% van de beschreven insecten.

Taxonomische belemmering

De vuurvlieg Aspisoma ignitum, Boven National Park, St. Eustatius/ Credit: Jan-Joost Mekkes

Helaas is er nog veel dat onderzoekers niet weten over de keverpopulaties van de noordelijke Caribische eilanden. Ook wel de “taxonomische belemmering” genoemd. Dit komt door de kloof tussen de lokale taxonomische kennis en een tekort aan opgeleide taxonomen in de regio. Er wordt zelfs geschat dat tot op heden slechts ongeveer 10-20% van de bekende keversoorten van de eilanden correct zijn geïdentificeerd.

Nieuwe waarnemingen

De snuitkever Trichobaris bridwelli, Oranjestad, St. Eustatius. Photo credit: Jan-Joost Mekkes

Twee nieuwe studies hebben deze kloof voor de eilanden Saba en Sint Eustatius overbrugd. Tussen 2008 en 2020 bezochten drie onderzoekers Saba en registreerden in totaal 22 verschillende keversoorten. Hiervan waren er 14 nieuw op Saba of bevestigde eerdere voorlopige waarnemingen en vier waren nieuw voor het Caribisch deel van het Koninkrijk der Nederlanden. Met deze nieuwe studie ligt het totale aantal geregistreerde keversoorten op Saba nu rond de 100.

Een onderzoeker op Sint Eustatius heeft in 2020 46 keversoorten kunnen verzamelen, waarvan 21 nieuw voor het eiland, waarvan 15 nieuw voor het Caribisch deel van het Koninkrijk der Nederlanden. Toegevoegd aan eerdere records, brengt dit nu het totale aantal bekende keversoorten voor het eiland op 117, wat volgens onderzoekers ongeveer een kwart is van het verwachte aantal soorten.

Rapporteer uw waarnemingen

Heb je kevers of andere insecten waargenomen?

Momenteel zit onderzoeker Jan-Joost Mekkes (jayjaymekkes@hotmail.com) op Sint Eustatius en Michiel Boeken (michiel.boeken@gmail.com) op Saba. Ze ontvangen graag uw kever- en andere insectenwaarnemingen.

Of upload uw waarnemingen en foto’s direct zelf in op de website www.Observation.org of download de gratis apps (iPhone (iObs) & Android (ObsMapp)).

Soortenrapporten door lokale gemeenschappen en toeristen zijn van onschatbare waarde voor inspanningen op het gebied van natuurbehoud om het publieke bewustzijn en de algemene bescherming van soorten te vergroten. Daarnaast werken de Dutch Caribbean Nature Alliance (DCNA), Observation International en Naturalis Biodiversity Center samen aan de ontwikkeling van een geautomatiseerde app voor het identificeren van soorten voor je telefoon. Uw geüploade foto’s zijn van grote waarde om dit mogelijk te maken. Neem voor vragen contact op met research@DCNAnature.org

Lees meer

De volledige lijst van de tijdens deze onderzoeken gedocumenteerde keversoorten vindt u in de Dutch Caribbean Biodiversity Database.

https://www.dcbd.nl/document/results-entomological-collecting-trip-st-eustatius-coleoptera

https://www.dcbd.nl/document/two-small-beetle-collections-saba-coleoptera

Published in BioNews 51 

Last December, a beetle catalogue for the Dutch Caribbean was published. This voluminous paper provides the first critical review of the beetle species reported for the islands. Only about a fifth of the species which are likely to be present on Aruba, Bonaire, Curaçao, Saba, St. Eustatius and St. Maarten are currently known. This leaves much to be discovered about the islands’ beetle fauna.

 In December 2020, a beetle catalogue for the Dutch Caribbean was published in the Dutch entomological journal Tijdschrift voor Entomologie. This voluminous paper, comprising 120 pages, provides the first critical review of the beetle species reported from the Dutch Caribbean up to 2020 as well as a history of beetle collecting, short biographies of the collectors who have been active on the islands, and a comprehensive Caribbean beetle bibliography. The need for an updated catalogue was inspired by the Naturalis St. Eustatius Scientific Terrestrial Expedition of 2015 (see BioNews 29).

Firefly (Aspisoma ignitum). Photo: Marijke Kanters

Beetles make up a considerable part of the Caribbean insect fauna but relatively little is known about them. The study of Caribbean beetles is seriously hampered by a big gap in taxonomic knowledge and a shortage of trained taxonomists for the region. Often, this makes it impossible to identify specimens to species or even genus level. The only relatively well-studied groups comprise the mostly larger-bodied members of families such as ground beetles (Carabidae), scarab beetles (Scarabaeidae), darkling beetles (Tenebrionidae), longhorn beetles (Cerambycidae) and more recently the, much smaller-bodied, members of the subfamily bark beetles (Curculionidae: Scolytinae). Modern revisions and keys to identify species from most other families are lacking.

The number of beetle species currently known from the various islands (Aruba: 50, Bonaire: 38, Curaçao: 131, Saba: 89, St. Eustatius: 96 and St. Maarten: 65) in comparison with the estimated number of species likely to be found on the islands (Aruba: 975, Bonaire: 1125, Curaçao: 1280, Saba: 440, St. Eustatius: 520 and St. Maarten: 785) illustrates the fact that there is still a lot more to discover about the islands’ beetle fauna.

Lady beetle (Cycloneda sanguinea). Photo: Jan-Joost Mekkes.

The “catalogue of the Coleoptera of the Dutch Antilles” is meant to serve as a starting point for further systematic and taxonomic research on the beetles of the Dutch Caribbean, for instance, the identification of the beetles collected during several recent visits to the islands. These include among others the extensive beetle collection from the 2015 St. Eustatius Scientific Terrestrial Expedition (in prep.), the beetles collected on St. Eustatius in 2020 during a trip by J.-J. Mekkes (in press), those collected on Saba in 2008 and 2009 by B.A. & M.J. Richardson and in 2019 and 2020 by M. Boeken (submitted) and some older material collected on Curaçao by C. van de Sande in 1975-76 (in prep.).

The “catalogue of the Coleoptera of the Dutch Antilles” was published “open access” and can be downloaded for free by all those interested from the website of Tijdschrift voor Entomologie. It can also be found on the Dutch Caribbean Biodiversity Database.

Report your sightings

Have you observed beetles or other insects? Report your nature sightings and photos on the website DutchCaribbean.Observation.org or download the free apps (iPhone (iObs) & Android (ObsMapp)).

Species reports by local communities and tourists are invaluable for nature conservation efforts to help increase public awareness and overall species protection. Besides, DCNA, Observation International and Naturalis Biodiversity Center are working together to develop on automated species identification app for your phone. Your uploaded photos are of great value to make this possible. For questions, please contact research@DCNAnature.org

Literature

Colijn, E.O. & J.-J. Mekkes 2021. Results of an entomological collecting trip to St. Eustatius. Coleoptera. Entomologische Berichten 81 (4): 175-183.

Colijn, E.O., K.K. Beentjes, R. Butôt, J.A. Miller, J.T. Smit, A.J. de Winter & B.B. van der Hoorn 2020. A catalogue of the Coleoptera of the Dutch Antilles. Tijdschrift voor Entomologie 162 (2-3): 67-186.

Colijn, E.O., M. Boeken, B.A. Richardson & M.J. Richardson 2021. Two small beetle collections from Saba (Coleoptera). Entomologische Berichten (submitted)

https://www.dcbd.nl/document/catalogue-coleoptera-dutch-antilles

Article published in BioNews 45

In January and February 2009 the third and fourth authors visited
Saba to sample the invertebrate fauna of tank bromeliads. They also
collected a small number of beetles during visits to the island in
October 2008 and October 2009. The second author paid a visit to Saba
in December 2019 and January 2020 to study red-billed tropicbirds.
During this stay he also collected several beetles and other invertebrates.
The two small beetle collections were identified by the first author.
Two specimens were identified to subfamily level, three to genus
level, two provisionally and fifteen to species level. Fourteen of the
taxa identified to genus or species level are new to Saba or constitute
confirmations of earlier provisional records for the island, four of these
are even new to the Dutch Antilles.
 

In February and March 2020 the second author visited St. Eustatius to
collect various insect groups. The beetles collected during this trip were
identified by the first author. Forty-six species could be identified to genus
or species level. Twenty-one of these were new for the island and 15 even
for the Dutch Antilles. This research brings the number of beetle species
currently known to occur on St. Eustatius to 117, which is about a quarter
of the number of species expected to be present on the island. There still
remains a lot to be discovered