Name: techniques for investigating the anatomy of the ant visual system
Uploaded: 2017-11-27T15:00:00
Description: Watch this Scientific Journal Video about Techniques for Investigating the Anatomy of the Ant Visual System at JoVE.com

We are grateful to Jochen Zeil, Paul Cooper and Birgit Greiner for sharing their knowledge in insect anatomy and for demonstrating several of the techniques we have described here. We are grateful to the talented and supportive staff at the Centre for Advanced Microscopy at ANU and The Microscopy Unit at MQU. This work was supported by a graduate scholarship to FRE and grants from the Australian Research Council (DE120100019, FT140100221, DP150101172).

1. Specimen Preparation
NOTE: It is necessary to first understand the relative location of the compound eye and ocelli to each other and on the head. This can be achieved by acquiring images of the dorsal view of the head. For this, we recommend processing samples either for photomicrography or using SEM techniques. Below are steps involved in both processes.
<ol>
	<li>Specimen collection
	<ol>
		<li>Collect and store specimens directly into 70% ethanol. Collect different ca...

<ol>
	<li>Zeil, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visual+homing:+an+insect+perspective.">Visual homing: an insect perspective.</a> Curr. Opin. Neurobiol. 22, 285-293 (2012).</li><li>Wehner, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Desert+ant+navigation:+how+miniature+brains+solve+complex+tasks.">Desert ant navigation: how miniature brains solve complex tasks.</a> J. Comp. Physiol. A. 189, 579-588 (2003).</li><li>Fent, K., Wehner, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ocelli:+a+celestial+compass+in+the+desert+ant+Cataglyphis.">Ocelli: a celestial compass in the desert ant Cataglyphis.</a> Science. 228, 192-194 (1985).</li><li>Warrant, E. J., Dacke, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visual+navigation+in+nocturnal+Insects.">Visual navigation in nocturnal Insects.</a> Physiology. 31, 182-192 (2016).</li><li>Taylor, G. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+dual+function+of+Orchid+bee+ocelli+as+revealed+by+x-ray+microtomography.">The dual function of Orchid bee ocelli as revealed by x-ray microtomography.</a> Curr. Biol. 26, 1-6 (2016).</li><li>H&#246;lldobler, B., Wilson, E. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Ants. , (1990).</li><li>Ali, T. M. M., Urbani, C. 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Entomol. 31, 131-142 (2006).</li><li>Bulova, S., Purce, K., Khodak, P., Sulger, E., O'Donnell, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Into+the+black+and+back:+the+ecology+of+brain+investment+in+Neotropical+army+ants+(Formicidae:+Dorylinae).">Into the black and back: the ecology of brain investment in Neotropical army ants (Formicidae: Dorylinae).</a> Naturwissen. 103, 3-4 (2016).</li><li>Narendra, A., Reid, S. F., Hemmi, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+twilight+zone:+ambient+light+levels+trigger+activity+in+primitive+ants.">The twilight zone: ambient light levels trigger activity in primitive ants.</a> Proc. R. Soc. B. 277, 1531-1538 (2010).</li><li>Narendra, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Caste-specific+visual+adaptations+to+distinct+daily+activity+schedules+in+Australian+Myrmecia+ants.">Caste-specific visual adaptations to distinct daily activity schedules in Australian Myrmecia ants.</a> Proc. R. Soc. B. 278, 1141-1149 (2011).</li><li>Moser, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eye+size+and+behaviour+of+day-and+night-flying+leafcutting+ant+alates.">Eye size and behaviour of day-and night-flying leafcutting ant alates.</a> J. Zool. 264, 69-75 (2004).</li><li>St&#246;ckl, A. L., Ribi, W. A., Warrant, E. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adaptations+for+nocturnal+and+diurnal+vision+in+the+hawkmoth+lamina.">Adaptations for nocturnal and diurnal vision in the hawkmoth lamina.</a> J. Comp. Neurol. 524, 160-175 (2016).</li><li>Zeil, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sexual+dimorphism+in+the+visual+system+of+flies:+the+compound+eyes+and+neural+superposition+in+Bibionidae+(Diptera).">Sexual dimorphism in the visual system of flies: the compound eyes and neural superposition in Bibionidae (Diptera).</a> J. Comp. Physiol. A. 150, 379-393 (1983).</li><li>Dacke, M., Nordstr&#246;m, P., Scholtz, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Twilight+orientation+to+polarised+light+in+the+crepuscular+dung+beetle+Scarabaeus+zambesianus.">Twilight orientation to polarised light in the crepuscular dung beetle Scarabaeus zambesianus.</a> J. Exp. Biol. 206, 1535-1543 (2003).</li><li>Greiner, B., Ribi, W. A., Warrant, E. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retinal+and+optical+adaptations+for+nocturnal+vision+in+the+halictid+bee+Megalopta+genalis.">Retinal and optical adaptations for nocturnal vision in the halictid bee Megalopta genalis.</a> Cell Tiss Res. 316, 377-390 (2004).</li><li>Warrant, E. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nocturnal+vision+and+landmark+orientation+in+a+tropical+halictid+bee.">Nocturnal vision and landmark orientation in a tropical halictid bee.</a> Curr. Biol. 14, 1309-1318 (2004).</li><li>Lattke, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Ants Standard Methods for Measuring and Monitoring Biodiversity. , 155-171 (2000).</li><li>Ribi, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> A Handbook in Biological Electron Microscopy. , 1-106 (1987).</li><li>Narendra, A., Ramirez-Esquivel, F., Ribi, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Compound+eye+and+ocellar+structure+for+walking+and+flying+modes+of+locomotion+in+the+Australian+ant,+Camponotus+consobrinus.">Compound eye and ocellar structure for walking and flying modes of locomotion in the Australian ant, Camponotus consobrinus.</a> Sci. Rep. 6, 22331 (2016).</li><li>Narendra, A., Greiner, B., Ribi, W. A., Zeil, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Light+and+dark+adaptation+mechanisms+in+the+compound+eyes+of+Myrmecia+ants+that+occupy+discrete+temporal+niches.">Light and dark adaptation mechanisms in the compound eyes of Myrmecia ants that occupy discrete temporal niches.</a> J. Exp. Biol. 219, 2435-2442 (2016).</li><li>Ribi, W. A., Zeil, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+visual+system+of+the+Australian+&amp;#34;Redeye&amp;#34;+cicada+(Psaltoda+moerens).">The visual system of the Australian &amp;#34;Redeye&amp;#34; cicada (Psaltoda moerens).</a> Arthr. Struct. Dev. 44, 574-586 (2015).</li><li>Ribi, W. A., Warrant, E. J., Zeil, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+organization+of+honeybee+ocelli:+regional+specializations+and+rhabdom+arrangements.">The organization of honeybee ocelli: regional specializations and rhabdom arrangements.</a> Arthr. Struct. Dev. 40, 509-520 (2011).</li><li>Ribi, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Colour+receptors+in+the+eye+of+the+digger+wasp,+Sphex+cognatus+Smith:+evaluation+by+selective+adaptation.">Colour receptors in the eye of the digger wasp, Sphex cognatus Smith: evaluation by selective adaptation.</a> Cell Tiss. Res. 195, 471-483 (1978).</li><li>Ribi, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrastructure+and+migration+of+screening+pigments+in+the+retina+of+Pieris+rapae+L.+(Lepidoptera,+Pieridae).">Ultrastructure and migration of screening pigments in the retina of Pieris rapae L. (Lepidoptera, Pieridae).</a> Cell Tiss. Res. 191, 57-73 (1978).</li><li>Lau, T., Gross, E., Meyer-Rochow, V. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sexual+dimorphism+and+light/dark+adaptation+in+the+compound+eyes+of+male+and+female+Acentria+ephemerella+(Lepidoptera:+Pyraloidea:+Crambidae).">Sexual dimorphism and light/dark adaptation in the compound eyes of male and female Acentria ephemerella (Lepidoptera: Pyraloidea: Crambidae).</a> Eur. J. Entomol. 104, 459-470 (2007).</li><li>Wipfler, B., Pohl, H., Yavorskaya, M. I., Beutel, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+methods+for+analysing+insect+structures+-+the+role+of+morphology+in+the+age+of+phylogenomics.">A review of methods for analysing insect structures - the role of morphology in the age of phylogenomics.</a> Curr. Opin. Insect Sci. 18, 60-68 (2016).</li><li>Streinzer, M., Brockmann, A., Nagaraja, N., Spaethe, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sex+and+caste-specific+variation+in+compound+eye+morphology+of+five+honeybee+species.">Sex and caste-specific variation in compound eye morphology of five honeybee species.</a> PLoS ONE. 8, e57702 (2013).</li><li>Somanathan, H., Warrant, E. J., Borges, R. M., Wall&#233;n, R., Kelber, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Resolution+and+sensitivity+of+the+eyes+of+the+Asian+honeybees+Apis+florea,+Apis+cerana+and+Apis+dorsata.">Resolution and sensitivity of the eyes of the Asian honeybees Apis florea, Apis cerana and Apis dorsata.</a> J. Exp. Biol. 212, 2448-2453 (2009).</li></ol>

The suite of methods outlined above allow for an effective investigation into the optical system of ants and other insects. These techniques inform our understanding of sampling resolution, optical sensitivity, and potential polarization sensitivity of the eye being studied. This knowledge provides an important foundation for physiological and behavioral investigation into their visual capabilities. Furthermore, while the methods detailed here have focused on ant visual systems, these techniques can be used on other inse...

Vision is an important sensory modality for most animals. Vision is especially crucial in the context of navigation for pinpointing goals, establishing and adhering to routes, and obtaining compass information1,2. Insects detect visual information using a pair of compound eyes and, in some cases, one to three dorsally-placed simple eyes called ocelli3,4,5.
The eyes of ants are of particular interest because, while ants are wonderfully diverse, they conserve some key characteristics across species. Despite dramatic variation in anatomy, size, and ecology, the vast majority of species are eusocial and live in colonies; as a result, different species face similar visual challenges in terms of navigating back and forth between a central place and resources. Across ants the same basic eye bauplan can be observed in animals ranging from 0.5-26 mm in body length, from exclusively diurnal to strictly nocturnal species, and from slow walking subterranean to leaping visual predators6,7,8,9,10. All of these staggering differences in ecology and behavior give rise to innumerable permutations of the same basic eye structures to suit different environments, lifestyles, and body-sizes11,12. As a consequence, studying the visual ecology of ants provides a veritable treasure trove of possibilities to the determined investigator.
Understanding the visual system of insects is essential in gaining an insight into their behavioral capabilities. This is apparent from integrative studies which nicely combine anatomy with ecology and behavior to a great success in a few insect groups (e.g., references13,14,15,16,17). Though the field of ant navigation and ant behavior in general has been quite successful, very little emphasis has been placed on ant vision outside of a few selected species. Here, we will elaborate on the techniques involved in investigating eye design of ants. While we will focus on ants, these techniques can be applied, with slight modifications, to other insects, too.

<table>
	<tbody>
		<tr>
			<td>Ant</td>
			<td>Myrmecia midas</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Stereomicroscope</td>
			<td>Leica M205 FA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sputter coater</td>
			<td>Pro Sci Tech</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Petri dish</td>
			<td>ProSciTech</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dissecting microscope</td>
			<td>Leica MZ6</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Insect Pin</td>
			<td>ProSciTech</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Colourless nail polish</td>
			<td>Non branded: from any cosmetic store</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Glass slide</td>
			<td>ProSciTech</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Razor blade</td>
			<td>ProSciTech</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Foreceps</td>
			<td>ProSciTech</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cover slip</td>
			<td>ProSciTech</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Compound microscope</td>
			<td>Leica DM5000 B</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Glutaraldehyde</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformalydehyde</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium Chloride (KCl)</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>di-Sodium Hydrogen phosphate (Na2HPO4)</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium di-Hydrogen Phosphate (KH2PO4)</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Chloride (NaCl)</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Osmium tetroxide</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Acetone</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Araldite Epoxy Resin</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Pasteur pipette</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Toluidie Blue</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hotplate</td>
			<td>Riechert HK120</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

techniques for investigating the anatomy of the ant visual system

This article outlines a suite of techniques in light microscopy (LM) and electron microscopy (EM) which can be used to study the internal and external eye anatomy of insects. These include traditional histological techniques optimized for work on ant eyes and adapted to work in concert with other techniques such as transmission electron microscopy (TEM) and scanning electron microscopy (SEM). These techniques, although vastly useful, can be difficult for the novice microscopist, so great emphasis has been placed in this article on troubleshooting and optimization for different specimens. We provide information on imaging techniques for the entire specimen (photo-microscopy and SEM) and discuss their advantages and disadvantages. We highlight the technique used in determining lens diameters for the entire eye and discuss new techniques for improvement. Lastly, we discuss techniques involved in preparing samples for LM and TEM, sectioning, staining, and imaging these samples. We discuss the hurdles that one might come across when preparing samples and how best to navigate around them.

The methods described here enable detailed study of the simple and compound eyes of ants. Imaging the dorsal view of the head using Z-stack photomicrography techniques allows one to obtain an overview of the layout of the visual system (Figure 1). This is good preparation for dissections and to determine the required sectioning angle. This technique is also useful for taking measurements such as head width, eye length, and ocellar lens diameters. SEM imaging ...

Watch this Scientific Journal Video about Techniques for Investigating the Anatomy of the Ant Visual System at JoVE.com

Techniques for Investigating the Anatomy of the Ant Visual System

This article outlines a suite of techniques in light and electron microscopy to study the internal and external eye anatomy of insects. These include several traditional techniques optimized for work on ant eyes, detailed troubleshooting, and suggestions for optimization for different specimens and regions of interest.

This article outlines a suite of techniques in light microscopy (LM) and electron microscopy (EM) which can be used to study the internal and external eye ...

The overall goal of this suite of microscopy techniques is to obtain detailed anatomical information of the ant visual system. This method can help address key questions in the field of visual ecology, to estimate various visual parameters, such as optical sensitivity, visual acuity, and size of the visual field. The main advantage of this technique is that it gives the comprehensive overview of a given visual system.It can also be adapted to use with many different species. To make the cornea replicas, use ants preserved in ethanol or mounted on a pin, or in Plasticine. If the head is relatively large, the remaining body parts can be removed.To begin, quickly spread fast-drying, colorless nail polish over the eye, using a toothpick, without scratching the eye. Let the polish set at room temperature. Then, use a fine insect pin to gently lift the replica from the head capsule surrounding the eye.And using forceps grasp the part of the replica that covers the head, but not the eye. Next, place the replica on a glass slide. There, use a razor blade to carefully trim excess material around the eye, while securing the replica.Before placing a cover slip over the replica, it may be necessary to make three to four fine partial radial slices to help flatten it. When placing the cover slip, document the replica's orientation on the slide. Then, seal the cover slip, using small dabs of nail polish on the corners, making certain that the liquid does not touch the replica.The slide is then ready to image using a compound microscope. To begin, anesthetize the ant and place it in a petri dish. If dye needs to be adapted for bright or dot conditions this should be done for a few hours before the dissection.If the dot conditions seem to be maintained, the dissection should be carried out in the red light. First, remove the antennae using forceps. Then, remove the mouth parts using a sharp razor blade.In large specimens, cut through the anterior part of the eye. In a small specimen, cut as close to the eyes as possible, without tugging on the brain, as this may tear out the retina. Next, orient the head and make a transverse incision, that removes the ventral portion of the head, which may include part of the ventral eye.Then, detach the head capsule with a coronal incision, just posterior to the compound eye. In this example, the transverse and coronal incisions are made simultaneously. Finally, transfer the dissected head capsule with the compound eyes to ice cold fixative.It's important to perform these steps quickly, to prevent tissue from degrading, so the tissue should go into the fixative within two minutes of the first incision. Following the text protocol, prepare the specimen and drain the excess resin. Then, place the specimen on the block in a vertical position, and if needed, use a little excess resin to secure it there.Label the block with paper labels embedded in the resin, or attached to the block. Then, cure the resin in a 60 degree Celsius oven, for 12 to 14 hours. Once cured, load the specimen into a clean envelope.Next, mount the block onto a microtome chuck. Before sectioning, first make certain that the specimen's orientation is appropriate for the sectioning plane. Under a dissecting microscope, trim the resin block using a razor blade.Then, remount the chuck onto the microtome arm, and angle the specimen. Next, fill the knife boat with distilled water using a syringe with a 0.45 micron filter. Load the water up to the edge of the knife.In some places the meniscus may be convex. Then, drain the boat until the meniscus is very slightly concave, but still reaches the edge of the knife. Now, slowly and carefully bring the knife towards the specimen, and align the block to the knife.Make frequent checks via the ocular. When the knife is close but not yet cutting the specimen start cranking the microtome wheel to complete the approach. Then, when approaching the region of interest in the block adjust the section collecting thickness.In this case, a diamond knife is used to make one micron sections. Then, from the filter equipped syringe place a series of small droplets of distilled water on a slide. To collect a section of interest, pick it up using an eyelash tool.And carefully, float the collected section onto a water droplet. Continue loading as many sections onto each slide as can fit. When a slide gets fully loaded transfer it to a hot plate at 60 degrees Celsius to evaporate the water, and adhere the sections to the slide.This takes about 15 to 20 minutes. Next, use another filter equipped syringe to deposit a drop of toluidine blue dye onto the slide. Place the drop on one end of the slide and spread it using the edge of a needle without touching or scraping the sections.Then, place the slide on the hot plate for 20 to 60 seconds. Afterwards, spray the slide with distilled water from a wash bottle, and use the hot plate to dry it off. Later, check the slides under the compound microscope and then image them.The described techniques enable a detailed study of the simple and compound eyes of ants. Imaging the dorsal view of the head using Z-Stack photomicrography provides an overview of the layout of the visual system useful for making gross measurements. SEM imaging provides the detail needed to resolve small eyes and the detail needed to identify the shape of each lens.Semi-thin sections imaged using light microscopy show the internal anatomy of an eye. Lens, crystalline cone, and rhabdomere dimensions can be measured at this resolution and magnification. Pigment cells, cone tract presence and rhabdomere shape distributions can also be studied.Ultra-thin sections imaged by TEM provide ultrastructure information, such as microvillar orientation, and for example, the width of the constricted crystalline cone tract. While attempting this technique, it's really important to be patient, to use clean instruments, and to use freshly made solutions. Following these experiments, additional behavioral or physiological experiments can then be carried out.These experiments will inform us about the functional visual abilities of the animal, relative to the eye anatomy. Using these techniques allows us to explore the diversity of visual systems, and how they have evolved to suit different lifestyles and different ecologies, in different species of ants. Though this method can provide insight into the ant visual system, it can also be used to study the visual system of other insects, as well as, other nervous tissues.Don't forget that working with fixatives and resins is extremely hazardous and precautions such as, working in the fume hood and wearing nitrile gloves, should always be taken.

Research

JoVE Journal

Environment

Methods for Performing Crosses in Setaria viridis, a New Model System for the Grasses

Methods for Performing Crosses in Setaria viridis, a New Model System for the Grasses

Setaria viridis is an emerging model system for C4 grasses. It is closely related to the bioenergy feed stock switchgrass and the grain crop foxtail ...

Empirical, Metagenomic, and Computational Techniques Illuminate the Mechanisms by which Fungicides Compromise Bee Health

Growers often use fungicide sprays during bloom to protect crops against disease, which exposes bees to fungicide residues. Although considered ...

Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx

Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx

Nitrogen oxides (NOx = NO + NO2) are a family of atmospheric trace gases that have great impact on the environment. NOx concentrations directly influence ...

Extraction of Organochlorine Pesticides from Plastic Pellets and Plastic Type Analysis

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment ...

Measuring and Mapping Patterns of Soil Erosion and Deposition Related to Soil Carbonate Concentrations Under Agricultural Management

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes ...

Methodology for Developing Life Tables for Sessile Insects in the Field Using the Whitefly, Bemisia tabaci, in Cotton As a Model System

Methodology for Developing Life Tables for Sessile Insects in the Field Using the Whitefly, Bemisia tabaci, in Cotton As a Model System

Life tables provide a means of measuring the schedules of birth and death from populations over time. They also can be used to quantify the sources and ...

Procedures of Laboratory Fumigation for Pest Control with Nitric Oxide Gas

Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. This paper provides detailed protocols for conducting NO fumigation on ...

Development of New Methods for Quantifying Fish Density Using Underwater Stereo-video Tools

The use of video camera systems in ecological studies of fish continues to gain traction as a viable, non-extractive method of measuring fish lengths and ...

Harvesting Venom Toxins from Assassin Bugs and Other Heteropteran Insects

Heteropteran insects such as assassin bugs (Reduviidae) and giant water bugs (Belostomatidae) descended from a common predaceous and venomous ancestor, ...

In Situ Hybridization Techniques for Paraffin-Embedded Adult Coral Samples

In Situ Hybridization Techniques for Paraffin-Embedded Adult Coral Samples

Corals are important ocean invertebrates that are critical for overall ocean health as well as human health. However, due to human impacts such as rising ...