1. Diversity of Ladybird Beetles (Coleoptera: Coccinellidae) in Tenerife and La Gomera (Canary Islands): The Role of Size and Other Island Characteristics.
- Author
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Romanowski, Jerzy, Ceryngier, Piotr, Vĕtrovec, Jaroslav, Zmuda, Christian, and Szawaryn, Karol
- Subjects
HARMONIA axyridis ,SPECIES diversity ,INTRODUCED species ,FIELD research ,BIOLOGICAL evolution ,LADYBUGS - Abstract
Simple Summary: The main assumption of the so-called theory of island biogeography is that larger islands are home to more species than smaller ones. However, species richness on an island is affected not only by its size but also by other features, such as the island's distance from the mainland or its geological age. The two Canary Islands Tenerife and La Gomera are a good model for testing the relationship between species richness and island area, as they differ considerably in size (the former has an area 5.5 times that of the latter) but are similar in location and age. They lie close to each other (less than 30 km apart) in the central-western part of the archipelago, about 300 km from the African coast. Both were formed as a result of volcanic activity some 11.5–12 million years ago. We compared the species composition and species richness of ladybird beetles on these two islands based on our field surveys and the literature data. As expected, clearly more ladybird species have been recorded on Tenerife (47 species) than on La Gomera (26 species). Being the largest of the Canary Islands, Tenerife has the richest ladybird fauna of all the islands in the archipelago, but it is also more susceptible to colonization by non-native ladybirds than the other islands: to date, ten species of non-native ladybirds have been recorded on Tenerife, compared to between three and seven on the other islands (five on La Gomera). Among the non-native ladybirds established on Tenerife (but not on any other island in the archipelago) is the harlequin ladybird (Harmonia axyridis), a highly invasive species of Asiatic origin that has spread nearly worldwide. This paper provides new data on the ladybird beetles (Coccinellidae) from two islands in the Canary archipelago: Tenerife, the largest island, and La Gomera, the second smallest. As they clearly differ in size but are similar in location and geological age, they are a suitable model for testing the species–area relationship. Our study shows that, in line with this main assumption of the theory of island biogeography, clearly more species occur on a large island (Tenerife) than on a small one (La Gomera). The field surveys documented the occurrence of 35 ladybird species on Tenerife (including 5 not previously reported from this island) and of 20 species on La Gomera (2 species new to the island). Coelopterus sp. collected on Tenerife (a single female that could not be identified to species) is the first record of this genus for the whole Canary Islands. Taking our data and previously published records into account, 47 species of Coccinellidae are known to occur on Tenerife and 26 species on La Gomera. Tenerife has by far the richest ladybird fauna of all the Canary Islands (the next in line, Gran Canaria, has 41 recorded species), but it also has the highest number of non-native ladybird species. All of the ten non-native species recorded in the Canary Islands are found on Tenerife, and for most of them, Tenerife was the island of their first appearance in the archipelago. This island, much more distant from the mainland than the other relatively large islands (Fuerteventura, Lanzarote), appears to be the main recipient of ladybirds immigrating to the Canary Islands. Tenerife can play this role probably because of its great habitat diversity and altitude variation, as well as intensive tourism and trade-related transport. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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