Brochosomal Coatings of the Integument of Leafhoppers (Hemiptera, Cicadellidae)

Gorb

2013

J. R. Soc. Interface.

Leafhoppers (Insecta, Hemiptera, Cicadellidae) actively coat their integuments with buckyball-shaped submicron proteinaceous secretory particles, called brochosomes. Here, we demonstrate that brochosomal coats, recently shown to be superhydrophobic, act as non-stick coatings and protect leafhoppers from contamination with their own sticky exudates-filtered plant sap. We exposed 137 wings of Alnetoidia alneti (Dahlbom), from half of which brochosomes were removed, to the rain of exudates under a colony of live A. alneti. One hundred and fifty-two droplets became stuck to the bared wings and only three to the intact wings. Inspection of the wings with a scanning electron microscope confirmed that the droplets that had hit the intact wings had rolled or bounced off the brochosomal coats. This is the first experimental study that tested a biological function of the brochosomal coats of leafhopper integuments. We argue that the production of brochosomes in leafhoppers and production of epidermal wax blooms in other sap-sucking hemipterans are alternative solutions, both serving to protect these insects from entrapment by their exudates.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Brochosomes protect leafhoppers (Insecta, Hemiptera, Cicadellidae) from sticky exudates

Gorb

2013

J. R. Soc. Interface.

“…Soon after moult, leafhopper adults and, in some lineages, also immatures release colloidal suspension of brochosomes through the hindgut and apply it with their legs onto the new integument. Once the liquid has dried out, brochosomes are further spread during bouts of grooming behaviour, in which leafhoppers rapidly brush their integuments with the legs bearing comb-like rows of specialized setae; as a result, the entire integument becomes coated with a thin pruinose layer of brochosomes [11,[16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

“…It appears that such strong water-repellence in leafhoppers-a group of exclusively terrestrial insects-primarily serves as protection from contamination by or getting trapped into liquid exudates produced by leafhoppers as a consequence of their feeding on plant sap [11,[16][17][18]21]. The physico-chemical properties of leafhopper exudates remain unstudied.…”

mentioning

confidence: 99%

Brochosomal coats turn leafhopper (Insecta, Hemiptera, Cicadellidae) integument to superhydrophobic state

Gorb

2013

Proc. R. Soc. B.

Leafhoppers (Insecta, Hemiptera, Cicadellidae) actively coat their integuments with brochosomes, hollow proteinaceous spheres of usually 200-700 nm in diameter, with honeycombed walls. The coats have been previously suggested to act as a water-repellent and anti-adhesive protective barrier against the insect's own exudates. We estimated their wettability through contact angle (CA) measurements of water, diiodomethane, ethylene glycol and ethanol on detached wings of the leafhoppers Alnetoidia alneti, Athysanus argentarius and Cicadella viridis. Intact brochosome-coated integuments were repellent to all test liquids, except ethanol, and exhibited superhydrophobicity, with the average water CAs of 165-1728, and the apparent surface free energy (SFE) estimates not exceeding 0.74 mN m 21. By contrast, the integuments from which brochosomes were removed with a peeling technique using fluid polyvinylsiloxane displayed water CAs of only 103-1298 and SFEs above 20 mN m 21. Observations of water-sprayed wings in a cryo-scanning electron microscope confirmed that brochosomal coats prevented water from contacting the integument. Their superhydrophobic properties appear to result from fractal roughness, which dramatically reduces the area of contact with high-surface-tension liquids, including, presumably, leafhopper exudates.

“…Secretions of these organs play important roles in the biology of different groups of Cicadomorpha [6][7][8]. For example, cicadellids actively coat their integuments with water-repellent sheaths of brochosomes, proteinaceous products of specialized Malpighian tubule segments [9][10][11][12]. It has been argued that the production of brochosomes had evolved in the common ancestor of Membracoidea [13].…”

Section: Introductionmentioning

confidence: 99%

Observations on the Biology and Anatomy of Myerslopiidae (Hemiptera, Membracoidea)

Psyche: A Journal of Entomology

2015

Adults and nymphs of Mapuchea chilensis (Nielson), from the poorly known family Myerslopiidae, were collected from the litter horizon of temperate forests and shrub bogs in southern Chile. The species apparently feeds on roots and creeping stems of angiosperms. Salivary sheaths of captive specimens terminated in vascular bundles. Indirect evidence suggests feeding on phloem sap. Both nymphs and adults are strong jumpers and both actively disperse, as evidenced by their capture in pan traps. The Malpighian tubules of this species produce no brochosomes and, unlike in most previously studied Membracoidea, comprise no specialized secretory segment. Each tubule comprises secretory cells scattered among excretory ones, a condition not previously known among Hemiptera.