Pete,
Well, my thinking on including small populations of individuals in the definition of the proposed dwc:Individual class (http://code.google.com/p/darwincore/issues/detail?id=69 and related issue http://code.google.com/p/darwincore/issues/detail?id=80) was simply based on practicality.  I know that collectors put bundles of grass individuals together on an herbarium sheet, bryophyte collectors have numerous moss individuals clumped together in a specimen, and entomologists put several individual insects of the same species collected at the same time and place together in the same jar.  I also take images that include several individuals of the same species (e.g. http://bioimages.vanderbilt.edu/baskauf/67323).  People collect different individuals at the same place and time and call them "duplicates".   In these cases, the person recording the Occurrence isn't interested (or perhaps CAN'T in the case of clonal plants where it might not be clear where one individual starts and another ends) separate out the individuals.  As I have conceptualized it, the purpose of being able to create instances of the class Individual is to be able to create named nodes that connect other resources.  I will not elaborate about that here because you can read about the idea in detail at Biodiversity Informatics 7:17-44 (https://journals.ku.edu/index.php/jbi/article/view/3664).  But the point is that any entity that meets my definition of Individual can usefully serve as such a node.  If clarification is needed about what "Individual" means in a particular circumstance, another proposed term (individualRemarks) can be used to elaborate.

There are circumstances such as you brought up (queen vs. worker ant) where it would be better to describe the biological individuals as separate dwc:Individual's.  In fact, it would probably ALWAYS be better to have Individuals be separate biological individuals if it is possible to do so.  But in cases where it's not possible (or if somebody in the past chose not to do so, as in the case of duplicate specimens), allowing small populations to be considered as Individuals still allows the benefits of them sharing common identifications and linking those identifications to multiple Occurrences. 

There is of course the problem of "collections" of Occurrences where Individuals of different species end up together in the same resource (see the Conclusions section of the above paper), e.g. contents of a pitfall trap, an image showing multiple species in their habitat,  and a specimen with evidence of parasitism by another species.  I haven't put enough thought into how to handle these situations to suggest a solution, but it does not seem out of the question to define some other term ("conglomeration" maybe?  "bag" and "collection" are already taken) to connect an Occurrence resource to multiple Individuals.  This in itself is a strong argument for why determinations should be associated with Individuals rather than Occurrences.  In the model that I described in the paper, an Occurrence has an "individualID" property that connects the occurrence to its determinations via the Individual.  But that wouldn't have to be the case.  An Occurrence could have a "conglomerationID" property that would connect it to the Conglomeration resource and that resource could then have several "individualID" properties that connect it to the multiple individuals with there separate determinations.  Anyway, more thought needs to go into this, but the problem does not seem unsurmountable. 

Steve

Peter DeVries wrote:
...

I am also wondering if the "individual" definition should be changed to mean one individual organism rather than a potential collection of individuals. Individuals from the same colony could be represented using a separate related vocabulary. Allowing multiple
individuals will cause problems for consuming applications. For instance, is the queen a separate individual or not? How do you differentiate between a photo of the queen vs. a photo of one of the workers. There are also potential problems even if the individuals
are all workers.

I have been thinking that for some attributes like character states, it might be best to have a family level ontology. In this example, you might have a "formicidae_ontology", that could be used to deal with individuals from the same colony as well as ant specific character states.


<rdf:Description rdf:about="http://example.org/individual/123412">

 <ant:colonyMateOf rdf:resource="http://example.org/individual/123414"/>
</rdf:Description>

This could be defined as a subproperty of dc:relation or something similar in the gbif/tdwg vocabulary.

- Pete

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