Sexual Dimorphism in the Compound Eye of Rhagophthalmus ohbai (Coleoptera: Rhagophthalmidae): I. Morphology and Ultrastructure

Lau, Ting Fan; Meyer-Rochow, Victor Benno

doi:10.1016/s1226-8615(08)60271-x

Cited by 15 publications

(13 citation statements)

References 39 publications

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“…from a sunny to a shadowy place to lay eggs. Interestingly, the highly sexually dimorphic firefly, Rhagophthalmus ohbai (Lau & Meyer-Rochow, 2006) shows a similar pattern to that of O. antiqua in that its female does not feed as an adult and is rather sedentary. However, the nocturnally-active wingless female firefly possesses an apposition eye with no more than 40 facets, while the fully-winged male has a functional superposition eye with more than 2000 facets.…”

Section: Functional Implication Of the Male And Female Eyementioning

confidence: 96%

The compound eye of Orgyia antiqua (Lepidoptera: Lymantriidae): Sexual dimorphism and light/dark adaptational changes

Lau¹,

Meyer‐Rochow²

2007

Eur. J. Entomol.

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Abstract. Structure and photomechanical changes upon light/dark adaptation in the superposition compound eyes of the highly sexually dimorphic Orygia antiqua were studied by light and electron microscopy. The eyes of the fully winged male differ from those of the wingless, sedentary female in several respects: they are significantly larger, display a more regular ommatidial array, have a wider clearzone and possess a much more substantial tracheal tapetum. However, the eyes of the female exhibit more pronounced photomechanical changes upon light/dark adaptation than those of the male. We believe that for females, on account of their limited mobility, it is necessary that their eyes can cope with widely fluctuating brightnesses, but that visual sensitivity and resolving power are less important to them than to the actively flying males. Although the latter may be attracted to the females by pheromones, males in their diurnal searches will have to visually avoid obstacles and predators. Moreover, because of their ability to fly, males can seek shelters or shaded areas and unlike the sedentary females avoid prolonged exposures to potentially hazardous light levels. This could explain why the eyes of the females exhibit more pronounced photomechanical responses to changes in ambient light levels.

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Section: Functional Implication Of the Male And Female Eyementioning

confidence: 96%

The compound eye of Orgyia antiqua (Lepidoptera: Lymantriidae): Sexual dimorphism and light/dark adaptational changes

Lau¹,

Meyer‐Rochow²

2007

Eur. J. Entomol.

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“…Studies of the compound eyes in the highly sexually dimorphic firefly Rhagophthalmus ohbai (Coleoptera: Rhagophthalmidae) (Lau & Meyer-Rochow, 2006) and the moth Orgyia antiqua have revealed that the sedentary, wingless females have much smaller and less well-organized compound eyes than their male counterparts. As an extension of our earlier research, we now report ultrastructural details of the eyes and retinae of males and females of the aquatic moth Acentria ephemerella Denis & Schiffermüller 1775 (see Denis & Schiffermüller, 1775), a species formerly assigned to the Pyralidae, but nowadays placed in the Crambidae, Acentropinae (Speidel, 2003).…”

Section: Introductionmentioning

confidence: 99%

Sexual dimorphism and light/dark adaptation in the compound eyes of male and female Acentria ephemerella (Lepidoptera: Pyraloidea: Crambidae)

Lau¹,

Gross²,

Meyer‐Rochow³

2007

Eur. J. Entomol.

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Abstract. In the highly sexual-dimorphic nocturnal moth, Acentria ephemerella Denis & Schiffermüller 1775, the aquatic and wingless female possesses a refracting superposition eye, whose gross structural organization agrees with that of the fully-winged male. The possession of an extensive corneal nipple array, a wide clear-zone in combination with a voluminous rhabdom and a reflecting tracheal sheath are proof that the eyes of both sexes are adapted to function in a dimly lit environment. However, the ommatidium of the male eye has statistically significantly longer dioptric structures (i.e., crystalline cones) and light-perceiving elements (i.e., rhabdoms), as well as a much wider clear-zone than the female. Photomechanical changes upon light/dark adaptation in both male and female eyes result in screening pigment translocations that reduce or dilate ommatidial apertures, but because of the larger number of smaller facets of the male eye in combination with the structural differences of dioptric apparatus and retina (see above) the male eye would enjoy superior absolute visual sensitivity under dim conditions and a greater resolving power and ability to detect movement during the day. The arrangement of the microvilli in the rhabdom of both genders suggests that their eyes are polarization-sensitive, an ability they would share with many aquatic insects that have to recognize water surfaces. Although sexual recognition in A. ephemerella is thought to chiefly rely on pheromones, vision must still be important for both sexes, even if the females are wingless and never leave their watery habitat. Females swim actively under water and like their male counterparts, which fly above the surface of the water, they would have to see and avoid obstacles as well as potential predators. This, together with a small incidence of winged females, we believe, could be the reason why the eyes of female A. ephemerella are less regressed than those of other sexually dimorphic moths, like for instance Orgyia antiqua. Another, but difficult to test, possibility is that male and female A. ephemerella have diverged in their behaviour and habitat preferences less long ago than other sexually dimo rphic moths.

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“…What the investigations by Lau and Meyer-Rochow (2006), Lau et al (2007a,b), and Meyer-Rochow and Lau (2008) as well as those by Zeil (1983) have shown is that males often possess larger eyes with more facets than their females and that ultrastructural differences occur, involving predominantly the width of the clear-zone, the size of the rhabdom and its volume as well as the extent of the reflecting tapetum. Eyes of males and females, at least in Operophthera brumata, (Fig.…”

Section: Compound Eye Sexual Dimorphismmentioning

confidence: 90%

“…Although the female attractant is pheromonal, males need their eyes to avoid obstacles while on the wing. The situation is thus not very different from that of the firefly species Rhagophthalmus ohbai , for whose eyes Lau and Meyer‐Rochow () have provided information on ultrastructural differences between male and female specimens. However, in this species the males not only use their eyes to avoid obstacles, but need them to locate the females’ glow (Lau et al ., ).…”

Section: Compound Eye Research Suggestionsmentioning

confidence: 99%

“…Investigations that involved tiny moths revealed the same trend (Honkanen & Meyer‐Rochow, ) and, moreover, showed that the species with reduced or abandoned clear‐zones had changed from the moth‐typical nocturnal lifestyle to the more diurnal one of a butterfly (Fischer et al ., , ). An additional approach to investigate body size‐related modifications to the clear‐zone of superposition eyes was used by Lau & Meyer‐Rochow (), who studied the microanatomy of the eyes of male and female Rhagophthalmus ohbai fireflies. In that species males have large eyes that seem functionally adapted to spot the light of the female firefly from the air (Lau et al ., ), but the wingless females possess no clear‐zones in their tiny eyes.…”

Section: Compound Eye Research Suggestionsmentioning

confidence: 99%

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Compound eyes of insects and crustaceans: Some examples that show there is still a lot of work left to be done

Meyer-Rochow

2014

Insect Science

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Similarities and differences between the 2 main kinds of compound eye (apposition and superposition) are briefly explained before several promising topics for research on compound eyes are being introduced. Research on the embryology and molecular control of the development of the insect clear-zone eye with superposition optics is one of the suggestions, because almost all of the developmental work on insect eyes in the past has focused on eyes with apposition optics. Age- and habitat-related ultrastructural studies of the retinal organization are another suggestion and the deer cad Lipoptena cervi, which has an aerial phase during which it is winged followed by a several months long parasitic phase during which it is wingless, is mentioned as a candidate species. Sexual dimorphism expressing itself in many species as a difference in eye structure and function provides another promising field for compound eye researchers and so is a focus on compound eye miniaturization in very small insects, especially those that are aquatic and belong to species, in which clear-zone eyes are diagnostic or are tiny insects that are not aquatic, but belong to taxa like the Diptera for instance, in which open rather than closed rhabdoms are the rule. Structures like interommatidial hairs and glands as well as corneal microridges are yet another field that could yield interesting results and in the past has received insufficient consideration. Finally, the dearth of information on distance vision and depth perception is mentioned and a plea is made to examine the photic environment inside the foam shelters of spittle bugs, chrysales of pupae and other structures shielding insects and crustaceans.

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Sexual Dimorphism in the Compound Eye of Rhagophthalmus ohbai (Coleoptera: Rhagophthalmidae): I. Morphology and Ultrastructure

Cited by 15 publications

References 39 publications

The compound eye of Orgyia antiqua (Lepidoptera: Lymantriidae): Sexual dimorphism and light/dark adaptational changes

The compound eye of Orgyia antiqua (Lepidoptera: Lymantriidae): Sexual dimorphism and light/dark adaptational changes

Sexual dimorphism and light/dark adaptation in the compound eyes of male and female Acentria ephemerella (Lepidoptera: Pyraloidea: Crambidae)

Compound eyes of insects and crustaceans: Some examples that show there is still a lot of work left to be done

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