Rigorous Morphological Studies Confirm That the Classical Object of Pest Control Chilocorus kuwanae Is the Same Species as Ch. renipustulatus (Coleoptera: Coccinellidae)

Abstract

The ladybug Chilocorus kuwanae, which was described in Japan, has been used for biological control of pests for 100 years. Chilocorus kuwanae was recently synonymized with Ch. renipustulatus described in Europe. The synonymy was based on the examination of few specimens. Our aim is to verify this synonymy. We studied all characters previously used to distinguish these taxa: eight metric and nine qualitative characters. Examination of 107 specimens from Japan and Sakhalin and 174 specimens from Europe showed that the ranges of variability in all characters in Asian and European specimens strongly overlap. There are no characters with interspecific hiatuses. Analysis with Amadon’s criteria showed that Asian and European specimens also do not represent different subspecies. Conclusions: (1) No differences between the specimens from Asia (Japan and Sakhalin) and Europe were found at specific or subspecific levels. Chilocorus kuwanae is a junior synonym of Ch. renipustulatus. (2) The releases of “Chilocorus kuwanae” in Europe and the Caucasus did not represent classical biological control since the same species was native to these regions. (3) A thorough taxonomical revision with the study of morphological variability should be conducted before the introduction of any species to new regions. (4) Taxonomical conclusions based on morphological studies should be confirmed by statistical methods.

History of the Biodiversity of Ladybirds (Coccinellidae) at the Black Sea Coast of the Russian Caucasus in the Last 120 Years—Does the Landscape Transformation and Establishment of Harmonia axyridis Have an Impact?

“…Our data have shown that the populations of five of these species still exist in the region ( Table 3 ). Besides that, specimens of C. kuwanae (Silvestri, 1909) introduced from Japan were released [ 7 ], but we have revealed that C. kuwanae (Silvestri, 1909) is the junior synonym of C. renipustulatus (Scriba, 1790), which is the native element of the ladybird fauna at the Black Sea coast of Russia [ 38 ].…”

The Structure of the Endophallus Is a New Promising Feature and a Key to Study of Taxonomy of the Subgenus Metallotimarcha of the Genus Timarcha (Coleoptera, Chrysomelidae) in the Caucasus

“…The author follows the classical rule [40,41], which was recently (successfully) tested by Bie ńkowski, Orlova-Bienkowskaja [42]: 97% of specimens in one sample should be separable from 97% of specimens in the other sample, to qualify these samples as representing different subspecies. Amadon [40] showed that this rule is fulfilled for a metric character if the following inequalities are true:…”

Topical Collection: Natural Enemies and Biological Control of Plant Pests

“…One article stressed the importance of rigorous morphological investigations to accurately identify predatory coccinellids ( Chilocorus species) before release for classical biological control of coccids [ 4 ]. The authors found that Chilocorus kuwanae Silvestri and Chilocorus renipustulatus (Scriba) were the same species.…”

“…kuwanae in Europe and the Caucasus did not represent classical biological control, since the same species (misidentified as C . renipustulatus ) were native to these regions [ 4 ].…”