Helopeltis antonii, also known as the tea mosquito bug, is a species of heteropteran found within the Miridae family. They have a relatively large geographical distribution and are a known pest of many agricultural “cash” crops such as cocoa, cashew, and tea. Subsequently, their impact negatively influences economic growth within the regions in which they inhabit. Thus, their impact on humans has caused them to be of great interest biologically, resulting in significant environmental implications.
Distribution Helopeltis antonii are found in a region known as the old-world tropics which encompasses places such as India, Northern Australia, Guinea, Vietnam, Tanzania, Nigeria, and Indonesia.Rebijith, K. B., R. Asokan, N. K. K. Kumar, K. K. Srikumar, V. V. Ramamurthy, and P. S. Bhat. 2012. DNA Barcoding and Development of Species-Specific Markers for the Identification of Tea Mosquito Bugs (Miridae: Heteroptera) in India. Environmental Entomology 41:1239–1245Srikumar, K. K., P. S. Bhat, T. N. Raviprasad, K. Vanitha, N. K. K. Kumar, K. B. Rebijith, and R. Asokan. 2013. Distribution of Major Sucking Pest, Helopeltis spp. (Hemiptera: Miridae) of Cashew in India. Proceedings of the Zoological Society 68:30–35 More specifically, they are more concentrated in the agricultural regions of the old-world tropics. In India their distribution is primarily found within the “cashew belt” which is located along the western coast and central regions of the country due to its high affinity for these plants. However, different nations grow certain crops in various locations within their borders. Crops that H. antonii prefer will ultimately determine their specific distribution within a country.
Identification of distribution H. antonii are often mistaken and misidentified with other Helopeltis species. Thus, identifying the exact geographical range of H. antonii has become a difficult process. However, recent advances in species identification though DNA barcoding has made it much easier. DNA barcoding is a rapid and relatively inexpensive identification technique that locates unique genetic markers in their DNA allowing for the accurate identification of not only H. antonii, but other species as well.
Mating Reproduction for H. antonii occurs in 4 stages—arousal, mounting, copulation, and termination of copulation—and occurs year-round.Devasahayam, S. 1988. Mating and Oviposition Behavior of Tea Mosquito Bug Helopeltis antonii Signoret Heteroptera Miridae. The Journal of The Bombay Natural History Society 85:212-215Srikumar, K. K., and S. P. Bhat. 2016. Pronotal Color Morphs and Influence of Weather Parameters on Population Trends of the Capsid Bugs, Helopeltis antonii and H. bradyi in Cashew Ecosystem. Entomologia Generalis 35: 269-279 Mounting, arousal, and termination of copulation occurs within a short time frame; copulation is much longer and more variable in length. Mating typically occur in shaded, covered areas
Arousal Arousal consists of both chemical and tactile stimuli. Pheromones play an important role in the chemical attraction of females for mating. Although these chemical cues are important, physical cues comprise the bulk of mate attraction and arousal. Males are the sole initiators for reproductive encounters. This first done through sexual identification of a female partner. Sexual identification is only possible when in close proximity of each other. Once a female is located, the male makes contact with the female by gently probing her body with his antennae. Receptive females remain passive, permitting the male to proceed. In contrast, non-receptive females move to escape any further male interaction.
Mounting Following the initial arousal, the process of mounting ensues. Males mount females on the posterior region of her body allowing the erect male rostrum to stroke the dorsal side of the female, just below the thoracic shield. This stroking behaviour quiets the female and allows for easier insertion of the male aedeagus into the female genital aperture. If insertion is not achieved the male begins a left to right stroking motion to aid in its insertion. Females can also kick or shake males off to prevent further progression of mating. When this occurs, males are quick to remount and re-attempt insertion of their aedeagus into the female genital aperture. Successful insertion leads to copulation.
Copulation Once insertion has been established the male twists around in an end-to-end fashion to allow for copulation. Once in this end-to-end position, both the male and female remain still until copulation has completed. This can last anywhere from 10 minutes to 2 hours.
Termination of copulation Following copulation, they abruptly disjoin, however, detachment can be often difficult due to the males' twisted position. Once separated both the male and female begin to feed and clean their own genitals and antenna—this feeding and cleaning behaviour typically occurs within a few steps from the site of copulation. Females do not respond to any other mating advances immediately following copulation. However, females typically reproduce more than once during their lifetime.Siswanto., R. Muhamad, D. Omar, and E. Karmawati. 2009. The Effect of Mating on The Eggs’ Fertility and Fecundity of Helopeltis antonii (Heteroptera: Miridae). Tropical Life Sciences Research 20:89-97. Interspecific mating has been known to occur between Helopeltis species, specifically between H. antonii and H. theivora. However, their mating results in the production of unviable eggs.Bhat, P., and K. K. Srikumar. 2013. Genitalia Structure Examination for Interspecific Mating of Helopeltis antonii and H. theivora. Current Science 105:23-25 The production of eggs following interspecific mating between H. antonii and H. bradyi has not been observed. This ability and inability to engage in interspecific mating is due to the difference in genital structure between females. Females of both H. antonii and H. theivora have sclerotized rings that are not fused, whereas, the females of H. bradyi have fused sclerotized rings in its genitalia. This difference acts like a “lock and key” model for genitalia.
Oviposition Males and females are able to reproduce and lay viable eggs after their first day of sexual maturity. Unmated females are capable of laying eggs; however, they are sterile. The sex ratio of males to females does not influence the number of eggs a female can lay but environments with a high ratio reduces female longevity due to mating exhaustion. Females that reproduce more than once lay a larger number of eggs during oviposition. Females probe plant tissues with the tip of their rostrum to find a suitable site for the deposition of their eggs. The exact reason behind site choice is unknown, but once found the female bends her abdomen to establish contact between her ovipositor and the plant tissue. The ovipositor is then inserted into the plant tissue and the eggs are deposited, below the epidermis and parenchymatous tissue of the plant, via abdominal contractions. The eggs are ovo-elongate and silvery-white in colour and are approximately 1.0x0.3mm in size. Abundance of eggs laid is also weather dependent. Conditions that yield higher temperatures and increased sun exposure result in a higher abundance; whereas cooler temperatures, less available sunlight, and increased rain exposure reduces abundance.
Development H. antonii experiences partial metamorphosis, otherwise known as hemimetabolous development, which is characterized by it transition from an egg to nymph and eventually into a matured adult.Visalskshy, N. P., C. Swathi and L. Frenita. 2019. Studies on the Biological Parameters of Helopeltis antonii Sign. (Hemiptera Miridae) on Psidium guajava L. Pest Management in Horticultural Ecosystems 25:32-36 This developmental pattern takes about 25 days from the time the eggs are laid to adulthood. The eggs take eggs 12–13 days to hatch followed by 12–13 days of progressive nymph instars. H. antonii experience 5 instars in total before reaching adulthood. During the first instar, the body appears light orange in colour and progresses to a deep orange in the second instar. During the third instar, the body beings to develop wing buds and a scutellar horn. Wing pads become visibly prominent as the fourth instar emerges. Finally, in the fifth instar, the wing pads cover half of the abdomen—with the wings being transparent—and the body is light brown in colour but darkens via sclerotization. Additionally, in the fifth instar, the dorsum of the thorax appears red in colour, the tergum of the abdomen a dull white, the dorsal abdominal segment a deep orange colour, and overlapped hemi-elytra covers over the abdomen with its distal end containing a triangular blackish-brown colouration.
The less-matured first, second and third instars tend to group close to each other and remain in proximity of their hatch site for feeding. In contrast, the more matured fourth and fifth instars tend to be more dispersed and feed in areas farther from their hatch site as a result. Matured females have a characteristic white patch present on their fifth abdominal segment.
Environmental influence Although colouration is an important identifying feature of H. antonii it is subject to variation due to variations in temperature and sunlight exposure. Red colour morphs tend to peak in abundance during October and reach their minimum abundance during February (for males) and June (for females). Black colour morphs peak during June for both sexes. A brownish-black colour morph is also seen within the population, but its abundance is low, and its frequency remains constant throughout the year.
Diet and feeding H. antonii are herbivorous insects that have been known to feed on more than 100 different plant species. The sites of feeding, on these plant hosts, are not localized. Rather, both adult and nymphs feed on various sites ranging from tender shoots, buds, stems, and even their fruiting bodies to obtain sap.Visalskshy, N. P., C. Swathi. 2016. Host Range and Off-Season Survival of Tea Mosquito Bug, Helopeltis antonii Sign. Pest Management in Horticultural Ecosystems 22:134-136 H. antonii possess modified mouthparts which work to form a long straw-like structure known as a “stylet”. This modified mouth part enables them to suck up sap from deep within the plant tissues that would not otherwise be as easily accessible.
Seasonal Consumption H. antonii feed on both native plants as well as agriculturally grown crops. However, their availability changes with the seasons. This change in availability is due to the different growth cycles host plants experience throughout the year. As host plants enter their fruiting or flushing stages, they begin to have a higher rates of sap production and as a result become targeted by H. antonii. In native, non-cultivated, habitats there appears to be a preference for certain types of host plants even when many others are present. During January to February Annona is preferred, from March to April neem is preferred, from May to August papaya is preferred, and from September to December Singapore cherry is preferred. In addition to the consumption of native plant species, agricultural “cash crops” such black pepper, cashew, cocoa, and tea as are often at high risk for consumption and damage due to their large-scale cultivation and ease of accessibility. However, their feeding schedule on these is agricultural crops are more restricted based due to growing and harvest seasons.
Plant preference Like the seasonal preference of plants, preference is also seen in consumption habits of fruits with respect to different plants. For example, in custard apples the immature fruits are preferred over the matured fruits. Whereas in the Singapore cherries there is no observed feeding preference for immature or mature fruits.
Biological mechanics