Pivot burrowing of scarab beetle (Trypoxylus dichotomus) larva

Many organisms live in the soil but only a little is known about their ecology especially movement style. Scarab beetle larvae do not have appendages to shovel soil and their trunk is thick compared to their body length. Hence, their movement through the soil is perplexing. Here, we established the observation and analysis system of larval movement and found that the last larval instars of Trypoxylus dichotomus burrow in two different ways, depending on the hardness of the soil. If the soil is soft, the larvae keep their body in a straight line and use longitudinal expansion and contraction; if the soil is hard, they flex and rotate their body. It is thought that the larvae adapt to diverse soil conditions using two different excavation methods. These results are important for understanding the soil ecology and pose a challenge to engineer of newer excavation technology.

Taxonomic revision of the Afrotropical scarab beetle genus Cerhomalus Quedenfeldt, 1884 (Coleoptera: Scarabaeidae: Orphninae)

The Afrotropical scarab beetle genus Cerhomalus Quedenfeldt, 1884 (Coleoptera: Scarabaeidae) is revised. Two new species are described: C. quedenfeldti sp. nov. and C. petrovitzi sp. nov. A new combination, Cerhomalus absconditus (Petrovitz, 1971) comb. nov., is established. The genus occurs in Central and West Africa with the majority of records from the Congo Basin. Keys, descriptions, illustrations of habitus and male genitalia, and distributional record map are given

Pivot burrowing of scarab beetle (Trypoxylus dichotomus) larva

Many organisms live in the soil but only a little is known about their ecology especially movement style. Scarab beetle larvae do not have appendages to shovel soil and their trunk is thick compared to their body length. Hence, their movement through the soil is perplexing. Here, we established the observation and analysis system of larval movement and found that the last larval instars of Trypoxylus dichotomus burrow in two different ways, depending on the hardness of the soil. If the soil is soft, the larvae keep their body in a straight line and use longitudinal expansion and contraction; if the soil is hard, they flex and rotate their body. It is thought that the larvae adapt to diverse soil conditions using two different excavation methods. These results are important for understanding the soil ecology and pose a challenge to engineer of newer excavation technology.

Pivot burrowing of scarab beetle (Trypoxylus dichotomus) larva

Scarab beetle larvae do not have appendages to shovel soil and their trunk is thick compared to their body length; hence, their movement through the soil is perplexing. Here, we found that the last larval instars of Trypoxylus dichotomus burrow in two different ways, depending on the hardness of the soil. If the soil is soft, the larvae keep their body in a straight line and use longitudinal expansion and contraction; if the soil is hard, they flex and rotate their body. It is thought that the larvae adapt to diverse soil conditions using two different excavation methods.

A first faunistic study on the tribe Oniticellini Kolbe, 1905 (Coleoptera: Scarabaeidae) of Baikunthapur Tropical Forest of the Himalayan foothills, West Bengal, India

Oniticellini Kolbe, 1905 is a paucispecific tribe of the scarab beetle subfamily Scarabaeinae. The tribe is composed of 256 described species worldwide, while from India, 26 species were recorded to date. Beetles belonging to this tribe are commonly known as paracoprid dung beetles and perform some remarkable ecological functions. Nevertheless, there is a dearth of knowledge on the occurrence of these beetles in the mega diverse tropical forests of the Himalayan foothills located in the north of the West Bengal state of India. A first faunistic account of the tribe Oniticellini Kolbe, 1905 from Baikunthapur Forest, located at the Himalayan foothills of the West Bengal state of India is presented. A total of five species of the tribe distributed over two genera Tiniocellus and Liatongus were recorded during multiple surveys of the scarab fauna of the Forest. All taxa were recorded for the first time from the area, while Tiniocellus spinipes (Roth, 1851) is a new record for the West Bengal State of India. Additionally, a preliminary checklist of Indian species of the tribe is also provided.

Preference of three scarab beetle species to floral cues

The role of floral visual cues was studied in both sexes of three nocturnal scarab beetle species (Holotrichia oblita, Holotrichia parallela, and Anomala corpulenta). Flower patterns were designed using n-petal rose curve and radial gradient tools. Bioassay of plain colored patterns showed that both sexes of H. oblita and H. parallela preferred yellow and white. In contrast, A. corpulenta showed sexual differentiation in preferences. Comparison between given radial gradient patterns and their color components indicated that a radial gradient was necessary in both sexes of H. oblita rather than both sexes of H. parallela to elicit the highest response. Sexual differentiation was found in A. corpulenta. Among 4-, 8-, and 12-petaled patterns, the 4-petaled patterns were most preferred by all of the test insects, regardless of species and sex. Choice assays that provided both odor and visual cues suggest that olfaction may be the primary sensory modality in the three scarab species.