Morphometrics of the Tropical Bed Bug (Hemiptera: Cimicidae) From Cape Coast, Ghana

Bed bugs, Cimex lectularius (L.) (Hemiptera: Cimicidae) and Cimex hemipterus (F.), have become established worldwide in recent years largely due to the development of insecticide resistance. However, limited attention has been given to ongoing morphological and macroevolutionary changes within the species and their populations, which could have implications for their control. Here, we evaluated whether bed bugs of the species C. hemipterus inhabiting different communities in Cape Coast, Ghana are undergoing segregation, which could lead to possible speciation. We also aimed to provide a morphometric description of all nymphal stages. Nine-bed bug populations of C. hemipterus were field-collected in Cape Coast and were subjected to geometric morphometric analysis. The multivariate parameters applied distinguished various populations from each of the locations, indicating the presence of morphologically distinct subpopulations of C. hemipterus. Shape-based segregation and shape changes associated with the insect pronotum (which is an important taxonomic character in the Cimicidae) were evident across the populations. Through this comparative study of C. hemipterus, we showed that possible subpopulations of this bed bug are being spread from Ghana. The nymphal stages (first-fifth) of C. hemipterus were distinguished by the length of the last three antennal segment and pronota width; such information contributes to the taxonomic knowledge of the species.

Morphological and Molecular Identification of Cimex hemipterus Fabricius, 1803 (Hemiptera: Cimicidae) and First Report of C. lectularius Linnaeus, 1758, in Madagascar

Bed bugs are hematophagous insects with a long history of presence in human communities. Over the last three decades, infestations by bed bugs in human dwellings have drastically increased, leading to a rise in bed bug concerns. This study was conducted in May 2019 in the Miarinarivo district of Madagascar. Eight locations with suspected infestations were inspected. Of these, five locations were found with active bed bug infestations. Overall, 23 (19 adults and four nymphs) specimens with numbers per apartment ranging from 2 to 6 were collected and analyzed using morphological and molecular approaches. Of 19 adults collected, 18 were morphologically identified as Cimex hemipterus (Hemiptera: Cimicidae), with the final adult identified as C. lectularius. Morphological identification of adults was confirmed by sequencing 450 bp fragment of COI gene. All four nymphs were also identified molecularly as C. hemipterus. Maximum likelihood phylogenetic tree of COI gene and sequence alignment of C. hemipterus specimens revealed the presence of two groups (first group clustered with previously reported haplotype from Asian and African countries and the second group encompassed a lesser known haplotype exclusively from Africa (Kenya and Senegal). This study presents low genetic diversity among C. hemipterus specimens and, for the first time, reports the occurrence of C. lectularius, known as temperate species, in Madagascar. These results can be helpful in control management strategies against these ectoparasites in this country.

Invasive Insect Pests of Forests and Urban Trees in Russia: Origin, Pathways, Damage, and Management

Invasive alien insects cause serious ecological and economical losses around the world. Here, we review the bionomics, modern ranges (and their dynamics), distribution pathways, monitoring, and control measures of 14 insect species known to be important invasive and emerging tree pests in forest and urban ecosystems of Russia: Leptoglossus occidentalis (Hemiptera: Heteroptera: Coreidae), Halyomorpha halys (Hemiptera: Heteroptera: Pentatomidae), Corythucha arcuata (Hemiptera: Heteroptera: Tingidae), Agrilus fleischeri, A. mali, A. planipennis, Lamprodila (Palmar) festiva (Coleoptera: Buprestidae), Ips amitinus, Polygraphus proximus (Coleoptera: Curculionidae: Scolytinae), Cydalima perspectalis (Lepidoptera: Crambidae), Acrocercops brongniardella, Cameraria ohridella, Phyllonorycter issikii, and P. populifoliella (Lepidoptera: Gracillariidae). We identified three major scenarios of tree pest invasions in the country and beyond: (1) a naturally conditioned range expansion, which results in the arrival of a pest to a new territory and its further naturalization in a recipient region; (2) a human-mediated, long-distance transfer of a pest to a new territory and its further naturalization; and (3) a widening of the pest’s trophic niche and shift to new host plant(s) (commonly human-introduced) within the native pest’s range frequently followed by invasion to new regions.

Early evidence of establishment of the tropical bedbug (Cimex hemipterus) in Central Europe

In recent decades, the world has witnessed a remarkable resurgence of bedbugs (Hemiptera: Cimicidae). Although populations of the common bedbug, Cimex lectularius L., expanded in temperate regions of its original distribution, the tropical bedbug, C. hemipterus (F.), increased its abundance in warmer regions, where it also had been historically distributed. However, C. hemipterus has recently been observed to be expanding to other areas, e.g. North Australia, Middle East, the United States and Russia. In other parts of Europe, few sporadic and ephemeral introductions of C. hemipterus were recorded until recently. We conducted an extensive sampling of European bedbug populations starting in 2002 and found that C. hemipterus has recently become locally established. Among 566 examined infestations, nearly all of which involved C. lectularius, C. hemipterus occurred in six infestations collected since 2019. In at least three cases, the social background of inhabitants of the infested properties indicated that tropical bedbugs likely spread within local communities. Using cytochrome oxidase subunit I, we linked five of the infestations to the most common haplotype found globally, and one to an African haplotype. In all infestations, we observed two kdr-associated mutations in the sodium channel gene, which are also commonly found across the world.