An ocellar "pupil" that does not change with light intensity, but with the insect age in Triatoma infestans

Insausti, Teresita C.; Lazzari, Cláudio R.

doi:10.1590/s0074-02762000000500024

Cited by 16 publications

(5 citation statements)

References 19 publications

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“…It may be that in bumblebees the shape of the iris is also variable, though no variations in shape have been noted between the four specimens in this study, and may be involved in light adaptation as in dragonfly ocelli (Stavenga et al , 1979). A similar, curved iris has been found in Triatoma infestans , though this does not constrict in response to light (Insausti & Lazzari, 2000).…”

Section: Role Of the Irissupporting

confidence: 72%

Using micro-CT techniques to explore the role of sex and hair in the functional morphology of bumblebee (Bombus terrestris) ocelli

Wilby

Aarts

Tichit

et al. 2018

Preprint

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Many insects have triplets of camera type eyes, called ocelli, whose function remains unclear for most species. Here, we investigate the ocelli of the bumblebee, Bombus terrestris , using reconstructed 3D data from X-ray micro computed-tomography scans combined with computational ray-tracing simulations. This method enables us, not only to predict the visual fields of the ocelli, but to explore for the first time the effect that hair has on them as well as the difference between worker female and male ocelli.We find that bumblebee ocellar fields of view are directed forward and dorsally, incorporating the horizon as well as the sky. There is substantial binocular overlap between the median and lateral ocelli, but no overlap between the two lateral ocelli. Hairs in both workers and males occlude the ocellar field of view, mostly laterally in the worker median ocellus and dorsally in the lateral ocelli. There is little to no sexual dimorphism in the ocellar visual field, suggesting that in B. terrestris they confer no advantage to mating strategies.We compare our results with published observations for the visual fields of compound eyes in the same species as well as with the ocellar vision of other bee and insect species.

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Section: Role Of the Irissupporting

confidence: 72%

Using micro-CT techniques to explore the role of sex and hair in the functional morphology of bumblebee (Bombus terrestris) ocelli

Wilby

Aarts

Tichit

et al. 2018

Preprint

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“…The pupil widens during the following twenty days, and the change in pupil size corresponds well to the growth of the corneal lens. The authors suggest that the pigment rings are linked to the development of the ocelli [17]. Ocelli of insects can also be equipped with pupils that change size as a response to light stimuli as has been observed in two locust species [18].…”

Section: Discussionmentioning

confidence: 90%

“…In kissing bugs ( Triatoma infestans ) Insausti and Lazzari [17] have specified a similar process, as we describe here for spiders. In T. infestans recently emerged adults show an elongated narrow pupil surrounded by pigment cells.…”

Section: Discussionmentioning

confidence: 98%

Pupil Size in Spider Eyes Is Linked to Post-Ecdysal Lens Growth

et al. 2010

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In this study we describe a distinctive pigment ring that appears in spider eyes after ecdysis and successively decreases in size in the days thereafter. Although pigment stops in spider eyes are well known, size variability is, to our knowledge, reported here for the first time. Representative species from three families (Ctenidae, Sparassidae and Lycosidae) are investigated and, for one of these species (Cupiennius salei, Ctenidae), the progressive increase in pupil diameter is monitored. In this species the pupil occupies only a fourth of the total projected lens surface after ecdysis and reaches its final size after approximately ten days. MicroCT images suggest that the decrease of the pigment ring is linked to the growth of the corneal lens after ecdysis. The pigment rings might improve vision in the immature eye by shielding light rays that would otherwise enter the eye via peripheral regions of the cornea, beside the growing crystalline lens.

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“…To some extent our data support this notion: total amounts of screening pigment granules do increase as the eye increases in size and dark/light adaptational changes in the width of the retinal layer become significantly more pronounced in mature individuals (cf. also Insausti and Lazzari, 2000). The reason why transversely-cut rhabdoms of dark-adapted stick insects seemingly possess more screening pigment grains in their retinula cells (although further away from the rhabdom's edge than under conditions of light adaptation) is, because at light adaptation most of the pigment migrates from the middle of the retinula cells to the extreme distal ends, thereby forming a narrow sleeve around the aperture (i.e., the proximal cone tip) of the ommatidium.…”

Section: Discussionmentioning

confidence: 99%

Post-embryonic photoreceptor development and dark/light adaptation in the stick insect Carausius morosus (Phasmida, Phasmatidae)

Meyer-Rochow

Keskinen

2003

Appl. Entomol. Zool.

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The aims of this paper have been (a) to document postembryonic eye growth in the common laboratory stick insect Carausius morosus and (b) to examine whether the capacity of the eye to adapt to changing light intensities varied with age. We found that number of facets, corneal thickness, ommatidial diameter, widths of cone and retinal layers, and rhabdom volume increased linearly. Interommatidial angles, pigment grain sizes, and microvillar diameters, however, remained approximately the same. On the basis of the morphometric data we calculated that sensitivity in the adult stick insect eye was at least tenfold that of the eye of first instar nymphs and could show that adults would be able to perceive a similar amount of detail at considerably dimmer ambient light than the smaller individuals. In terms of resolving power this means that light-and dark-adapted first instar stick insects possess acceptance angles of 5.3°a nd 8°, respectively and that the corresponding figures for the adult eye are 4.7°and 7.3°. The bigger (and more lightsensitive) eye of fully grown C. morosus makes protection against radiation damage a more serious issue in the adult individual than the small first instar. The findings explain why smaller (ϭyounger) stick insects are less nocturnal than mature, fully-grown individuals. It is, thus, not surprising to see that dark/light adaptational photomechanical changes affecting pigment position and rhabdom widths, are more pronounced in the eyes of the adults.

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An ocellar "pupil" that does not change with light intensity, but with the insect age in Triatoma infestans

Abstract: The simple eyes (ocelli)

Cited by 16 publications

References 19 publications

Using micro-CT techniques to explore the role of sex and hair in the functional morphology of bumblebee (Bombus terrestris) ocelli

Using micro-CT techniques to explore the role of sex and hair in the functional morphology of bumblebee (Bombus terrestris) ocelli

Pupil Size in Spider Eyes Is Linked to Post-Ecdysal Lens Growth

Post-embryonic photoreceptor development and dark/light adaptation in the stick insect Carausius morosus (Phasmida, Phasmatidae)

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