▁certain ▁chemical s ▁over ▁others . ▁For ▁Eug loss a ▁imperial is , ▁studies ▁have ▁shown ▁that ▁there ▁is ▁a ▁significant ▁tr end ▁in ▁chemical ▁preference ▁for ▁c ine ole ▁during ▁later ▁times ▁in ▁the ▁year ▁as ▁opposed ▁to ▁m eth yl ▁sal ic yl ate . ▁In ▁the ▁local ▁fra gr ance ▁environment , ▁a ▁shift ▁in ▁the ▁wind ▁direction ▁is ▁another ▁factor ▁which ▁may ▁also ▁cause ▁another ▁fra gr ance ▁' hot ▁spot ' ▁to ▁be ▁included ▁in ▁the ▁od or ▁pl ume ▁for ▁e ug loss ine ▁be es . ▁ ▁Ne otrop ical ▁orch ids ▁themselves ▁often ▁exhib it ▁elaborate ▁adapt ations ▁involving ▁highly ▁specific ▁pla cement ▁of ▁pol len ▁packets ▁( pol lin ia ) ▁on ▁the ▁bodies ▁of ▁the ▁male ▁orch id ▁be es ; ▁the ▁specific ity ▁of ▁their ▁pla cement ▁ens ures ▁that ▁cross - pol lin ation ▁only ▁occurs ▁between ▁orch ids ▁of ▁the ▁same ▁species . ▁D ifferent ▁orch id ▁be e ▁males ▁are ▁attract ed ▁to ▁different ▁chemical s , ▁so ▁there ▁is ▁also ▁some ▁specific ity ▁regarding ▁which ▁orch id ▁be es ▁visit ▁which ▁types ▁of ▁orch id . ▁The ▁early ▁description ▁of ▁this ▁pol lin ation ▁system ▁was ▁by ▁Charles ▁Dar win , ▁though ▁at ▁the ▁time , ▁he ▁believed ▁the ▁be es ▁were ▁females . ▁Not ▁all ▁orch ids ▁util ize ▁e ug loss ines ▁as ▁pol len ▁vectors , ▁of ▁course ; ▁among ▁the ▁other ▁types ▁of ▁insect s ▁explo ited ▁are ▁other ▁types ▁of ▁be es ,