ID guide | introduced ants

Best practices

This page is adapted from Lucid Player help ( and USDA-CPHST Lucid training workshops.

During an identification session, Lucid allows you to choose any character (i.e., a character and its associated states) from the Characters Available list at any time. However, “stepping” through the key in a structured and sensible way will make your task of identification more efficient. Below are recommendations for increasing your efficiency and decreasing the amount of time required for identifying an unknown specimen using Lucid Player.

Become familiar with the specimen
First, become familiar with the characteristics of the specimen you wish to identify. If you are also familiar with the keys in this tool, then you may already know many of the specimen's characteristics. Briefly reviewing these characteristics before you start will make it easier for you to proceed through the identification.

No set order for selecting characters
Browse the list of Characters Available and start with the easy characters, or those characters you are most familiar with. The principles of dichotomous keys, in which the couplets must be answered in a preset order, are very familiar to most key users who often automatically apply these principles to a matrix key. Although Lucid lists the characters of a key in an initial sequence in the opening window, this does not mean that the characters must be selected in that order. You can select any character from any position in the list.

Antkey has a variety of characters, ranging from those dealing with obvious and simple characters to those dealing with characters that may be minute or difficult to interpret. Always start by browsing the list of Characters Available for obvious characters that you can quickly answer, as opposed to getting stuck on the first one. Lucid software is designed to overcome problems associated with difficult characters.

It's okay to skip characters
In looking through the characters, you may not be sure which state of a character to choose, or a character or state may be broken off or unclear on your specimen. Skipping the character entirely in such cases is always an option.

Use illustrated character notes
As you work through the list of Characters Available, you may find some characters or character states that you do not understand. If so, review the illustrations that are associated with the characters and states and look them up in the glossary. In fact, it is a good idea to check the illustrations before using any character for the first time, and to become familiar with these for all the characters.

Choosing multiple character states
You can always choose multiple states (more than one state of a character) if you are uncertain which state is the correct one to choose for a particular specimen. Lucid software is designed to allow you to choose as many states as you require from any one character. Within the program's logic, these states will be connected by an “or” link. This will cause Lucid to search for all taxa with any of the states you select. As a general rule, if you are unsure which of two or more states your specimen has, then choose them all. That way, you can be sure that your target taxon will remain in Taxa Remaining. [Note that in the Lucid3 Player users can choose the matching method option of “all states” rather than the usual default of “any states”. See Help for more information.]

Find the best character to address next
When you have dealt with all the obvious characters, use Lucid's “Best” function to suggest the remaining character that will give you the most efficient next step. The Best algorithm will assess which of the remaining characters and states available will best reduce the list of Taxa Remaining. The Lucid Player has two “Best” modes: Find Best and Sort Best.

Find Best – In the Lucid3 Player, clicking the Best button will cause the Player to move to and open the best available character. Next Best and Previous Best buttons on the toolbar allow navigation through the characters list, if you have difficulty addressing the first character nominated. If the list of Taxa in Taxa Remaining changes after choosing a character as suggested by Best, you should click the Best button again to recalculate the best character to address next.

Sort Best – Sort Best will reorder the Characters Available list so that characters are sorted from best to worst. After a Sort Best, scan the top of the list for characters that you can answer most easily. [Note that Sort Best only works using List View - a tree representation of characters cannot be sorted.]

Other Lucid3 Player tools
You may find other Lucid3 tools helpful while navigating character choices, such as Shortcut charactersPrune Redundants, and Calculate Differences. Explanations about how to use these functions are available through the Lucid Player Help menu.

What if no taxa remain?
This will happen sooner or later in one of your Lucid sessions. If no taxa are listed in the Taxa Remaining window, then it simply means that no taxa in the database match the set of states you have selected. Several explanations are possible, but these are some of the most common:

  • You have made an error in one or more of states you have selected. This is the most likely error for any situation in which no taxa remain.
  • The taxon may be undescribed or not included in the key. In this case Lucid cannot identify the specimen because its characters are not represented in the key's data tables.
  • The key author may have made an error when constructing the key. This is unlikely, but it can happen. If, after carefully checking all the characters and states and checking that the specimen you are attempting to identify would be expected to be included in the key, then a key construction error may be present.

Whichever of the above situations is suspected, you must very carefully review your chosen characters and determine which ones you are uncertain about. Try unselecting uncertain states one by one to see what effect each has. One or more taxon may move back into the Taxa Remaining window. In difficult cases, you may need to “play” with the key, adding or deleting states progressively to try to find the best matching taxon.

What if several taxa remain
Never assume that you will always end up with one taxon remaining. Some taxa in the key may be very hard to differentiate, except when using difficult or obscure characters. Sometimes, after you have addressed all the characters, you may have a short list of taxa remaining instead of just one taxon. You are still much closer to an identification than you otherwise would have been. You may then have to carefully check your specimen against associated information for the remaining taxa, especially the fact sheets, or refer to more advanced or specialist reference sources.

In some cases, if you have a short list of taxa remaining, but have not addressed all the characters, it may be easier to check your specimen against information associated with these remaining taxa. This can sometimes be faster than trying to find a character that will discriminate among the remaining taxa. If your taxon does not look similar to any of the taxa remaining, you can use the same strategy described above, of unselecting states one by one, or “playing” with the key, to find the best matching taxon.

Checking the result
Once you have made a preliminary identification, check the additional information available in the fact sheet provided for the taxon. Getting a possible name for a taxon from a key is not the end of an identification. You may have made errors, or your specimen may be a taxon that is not in the key. In these cases, the key may have provided you with the wrong name. The associated information is provided to give you a good indication as to whether the answer is correct.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith