## 5 Conclusions  
In this research, the effects of volatile blends and individual compounds emitted from fresh and aged cattle dung on the olfactory response of horn flies and on the oviposition of female horn flies were successfully evaluated. The olfactory response and the egg-laying of horn flies were influenced by volatile cues emanated from cattle feces. Volatile cues from fresh cattle dung were preferred by flies of both sexes and by female flies for egg-laying rather than aged dung. Moreover, \(p\)-cresol and \(\alpha\)-pinene were attractive to female horn flies, and they elicited a higher oviposition. Nonetheless, \(p\)-cresol was unattractive to males. Contrarily, \(\beta\)-pinene was an egg-laying deterrent, and \(\beta\)-caryophyllene was not influential on the oviposition, although these terpen were attractive to both sexes of flies. \(D\)-Limonene was not active in the horn fly egg-laying and was also unattractive to female flies. Therefore, \(p\)-cresol and \(\alpha\)-pinene may be responsible, in part, for the dung selection by female horn flies searching for oviposition sites. However, more single semiochemicals and mixtures of these, in different concentrations, should be tested on the olfactory and oviposition behavior of horn flies. Additionally, more studies are necessary to establish significant differences between the volatile profiles from cattle dung.  
The role of volatile cues emanated from cattle dung involved in the dung selection and oviposition of horn flies had been unexplored, until now. Principally, studies with host and dung semiochemicals were centered in stable fly behaviors. Moreover, the behavioral responses of horn flies in laboratory and in field have been tested to very few semic chemicals from cattle hosts or cattle dung. The use of semiochemicals has demonstrated being a promising tool in stable fly management. Stable fly trap innovations have included the addition of host-associated attractive odorants, principally phenol and \(m\)-cresol, to increase capture rates. However, innovative trapping technologies to catch horn flies have been unexplored. Thus, the present research could contribute to the development of new approaches for the control of the horn fly using semiochemicals as lures in fly traps and simultaneously emitting repellents from cattle, as part of a \"push-pull\" strategy.  
Conceptualization, J.E.; Formal analysis, I.S., J.A., N.A., M.L. and W.A.; Investigation, J.E., J.A., I.S. and W.A.; Methodology, J.E., I.S., J.A., N.A., M.L. and E.M.U.; Project administration, J.E.; Resources, J.E., E.M.U. and A.Q.; Software, J.E. and M.C.-F.; Writing--original draft, J.E. and J.A.; Writing--review and editing, J.E. All authors have read and agreed to the published version of the manuscript.  
This research and the APC were funded by ANID-FONDECYT project, grant number 11220808.  
Data Availability StatementData are contained within the article.  
The authors would like to acknowledge the ANID-FONDECYT project (grant number 11220808), which provided support for this research; Campo Experimental Maquehue-UFRO; and Instituto de Investigaciones Agropecuarias (INIA), Centro Regional de Investigacion Carillanca.  
The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.